FEMA Nonstructural Earthquake Hazard Mitigation Training

FEMA Nonstructural Earthquake Hazard Mitigation Training
Rapid Visual Screening of Buildings for Potential Seismic Vulnerability Fred Krimgold Virginia Tech CDM5 December 7, 2010 Slide 1 – Title This presentation describes a procedure for identifying nonstructural elements that may pose a hazard in the event of an earthquake. The primary focus of this presentation is to help the reader understand how to conduct a survey of a building to identify nonstructural items that are vulnerable in an earthquake and most likely to cause personal injury, costly property damage, or loss of function if they are damaged. The Federal Emergency Management Agency (FEMA) provided the funding for developing this presentation. Speaker Notes

Documents Slide 2 – Documents The original and current project produced two reports: the FEMA 154 Handbook and FEMA 155, the supporting Documentation. The Handbook, on the left, provides detailed procedures for rapid visual screening of building for potential seismic hazards. Detailed methodology and background information are contained in the companion Supporting Documentation report, shown on the right. The FEMA 154 Handbook was the first in a series of FEMA-sponsored resource documents intended to facilitate the mitigation of hazards posed by existing buildings. Other FEMA-sponsored documents provide methods for detailed evaluation of buildings that have been identified as potentially hazardous and for rehabilitation of hazardous buildings. FEMA 310 Handbook for the Seismic Evaluation of Existing Buildings- A Prestandard, is the current edition of the handbook used for detailed seismic evaluation of existing buildings. FEMA 310 supersedes FEMA 178. The current handbook for seismic rehabilitation of existing buildings is FEMA 356 Handbook for Seismic Rehabilitation of Existing Buildings – A Prestandard. FEMA 356 supersedes FEMA 273. Speaker Notes

FEMA 154 Table of Contents Introduction Planning and Managing Rapid Visual Screening (RVS) Completing the Data Collection Form Using the RVS Procedure Results Example Application of Rapid Visual Screening Appendices Slide 4 – Table of Contents This slide shows the title of the five chapters in the Table of Contents of FEMA 154: Chapter 1 is the introduction. Chapter 2 describes the planning and managing of the Rapid Visual Screening (RVS). Chapter 3 describes the procedures for completing the Data Collection Form. Chapter 4 describes using the RVS Procedure Results. Chapter 5 provides examples of the use of the RVS procedure. Following the 5 chapters, there are six appendices, labeled A through G, that include background information on such topics as seismicity, reviewing structural drawings, and assessing the building characteristics from an exterior survey. Note to Trainer: It is recommended that all of the students receive a copy of the FEMA 154 Handbook at the beginning of the presentation. We recommend encouraging further study of the handbook, including the appendices, for additional insight into the rapid visual screening of buildings for potential seismic hazards. Speaker Notes

Key Questions City Vulnerability Assessment
What is our building stock? What is the risk for occupants? What is the risk to property and business? How can this risk be managed and reduced? What happens to the city if we do nothing?

Outline of Presentation
FEMA Nonstructural Earthquake Hazard Mitigation Training Outline of Presentation Description of Procedure Behavior of Buildings Building Types and Typical Damage Basic Scores and Score Modifiers Occupancy and Falling Hazards Implementation of Procedure Example Applications Slide 5 – Presentation Outline This presentation is organized into these main topics: A description of the procedure A discussion of the earthquake behavior of buildings A description of standard building types and their typical seismic performance characteristics A description of the basic scores used in the RVS procedure and the score modifiers A discussion of occupancy and falling hazards A discussion of the implementation of the procedure A presentation of example applications of the procedure Note to the Trainer: The trainer is encouraged to modify and supplement the slides and narrative in the original FEMA 154 presentation with slides and narrative reflecting: his or her own experience, local building construction or special situations, and experience of the intended participants. The trainer may modify the material wherever it is appropriate, using standard PowerPoint® procedures. However, to keep modified and unmodified presentations distinct and recognizable, the trainer should add a note to this slide to indicate that revisions were made. Speaker Notes

Purpose and Limitations of Procedure
FEMA Nonstructural Earthquake Hazard Mitigation Training Purpose and Limitations of Procedure Purpose Screen for potential seismic hazards Identify buildings that may be hazardous Limitations Some hazardous buildings might not be identified Some adequate buildings might be identified as hazardous Accurate results dependent on experience of screener and thoroughness of pre-field activities Slide 7 – Purpose and Limitations The procedure presented in the handbook is meant to be preliminary screening phase of a multi-phase program for identifying, evaluating, and rehabilitating hazardous buildings. As such, it is a “screening only” procedure to identify buildings where reasonable doubts about earthquake resistance may exist. The procedure is based on known characteristics of buildings. When this procedure is used, some critical information about a building’s seismic resisting characteristics may not be visible, and as a result, the procedure may not lead to the building being characterized as potentially hazardous. More information that can be obtained regarding the building, such as from interior access and a review of building plans, can improve the likelihood of identifying potentially hazardous characteristics. Conversely, some building identified as hazardous using the RVS procedure may prove to be adequate based on subsequent evaluation. It is therefore important to emphasize that the results are preliminary and dependant on further evaluation. Buildings identified as potentially hazardous must be analyzed in more detail by a professional engineer experienced in seismic design. The procedure for the detailed evaluation are not described in this handbook, but can be performed using FEMA 310. The results obtained from the RVS procedure is strongly affected by the experience of the screener. Also, the thoroughness of the pre-field trip activities, such as determination of code dates, seismicity, and soil type, can influence the results. Speaker Notes

Seismic Hazard Map High Moderate Low Slide 9 – Seismic Hazard Map This map of the contiguous 48 states shows three levels of seismic hazard used for this procedure: low, moderate, and high. The map levels are based on the current US Geological Survey (USGS) maps of probable seismic hazard. The preparation of the maps considers the magnitude and frequency of past earthquakes, the location of known faults, and the expected earthquake shaking attenuation. These maps are based on an earthquake with a 2 percent chance of being exceeded in 50 years, which is also referred to as an earthquake with an average return period of 2475 years. These maps, used in the second edition of FEMA 154, are different than those used in the first edition for a couple of reasons. First, more information has been accumulated regarding the seismic hazards throughout the country. Second, the earthquake probability used in creating this map is different than that used in the first edition. In the first edition, the earthquake hazard was based on an earthquake with a 10 percent probability of being exceeded in 50 years, or a 475 average return period. The definition of the regions of seismicity is based on two parameters, the spectral acceleration at short periods and the spectral acceleration at 1 second periods. The maps have been simplified to present the seismicity based on the highest seismicity in each county. In some areas, the variation is seismicity within a county could allow the use of lower seismicity at some locations within a county. The USGS web site, as well as other sources, can provide the seismicity parameters for a location based on zip code rather than by county. Users should be encouraged to use the USGS web site to obtain more accurate seismic parameters that can be used to determine the appropriate regions of seismicity for the buildings being studied. Speaker Notes

Seismicity Region Definition
FEMA Nonstructural Earthquake Hazard Mitigation Training Seismicity Region Definition Spectral Spectral Region of Acceleration Acceleration Seismicity (short period (long period or or 0.2 sec) 1.0 sec) Low < g < g ≤ 0.167 g ≤ 0.067 g Moderate Slide 12 – Seismicity Region Definition This slide presents the criteria that is used to determine the region of seismcity. The spectral acceleration values for short period (0.2 seconds) and for long periods (1.0 second) are compared to the values in this table. The region of seismicity is based on the higher seismicity of that obtained using the short period acceleration and the long period acceleration. It is important to note that the values of seismicity provided by the USGS web site should be divided by 100 before comparing to the values in this table, since the values in this table are presented in g (the acceleration of gravity) whereas the values from the USGS web site are in percent g. < 0.50 g < 0.2 g ≤ 0.50 g ≤ High 0.20 g Speaker Notes

Data Collection Form Seismicity Building Type Basic Score Score Modifiers Slide 13 – Data Collection Form The FEMA 154 handbook provides separate forms for each of the three regions of seismicity; low, moderate, and high. The applicable region of seismicity is indicated on the top right-hand corner of each form. Although the layout of the three forms is identical, there are important differences in the numeric values on the forms. It is therefore important to be sure to used the correct form. Once the region of seismicity is determined and the appropriate form is selected, the form is then used to record building identification and occupancy information. A copy of the form is used to record information on each building such as the basic building type, the applicable score modifiers, a calculation of the final score, and a determination of whether the building should receive further evaluation. The form also includes spaces for sketches and for a photograph of the building, places for recording information regarding the occupancy and the presence of falling hazards, and a place to list comments. Final Score Evaluation Speaker Notes

Building Types Building Materials Wood Steel Concrete Masonry Lateral Force Resisting System Shear Wall Moment Frame Braced Frame Slide 14 – Building Types Visual determination of the construction material for the building and the lateral force resisting system is a critical part of the procedure. The basic construction materials typically used are wood, steel, concrete, and masonry. The other factor that influences the building type is the lateral force resisting system used in the building. Three of the more common types of lateral force resisting system are shear walls, moment-resisting frames, and braced frames. The FEMA1 154 guidelines provide information as to how to distinguish the building materials and the lateral force resisting system, which together determine the building type. The building type is the single most important factor in the procedure for determining the earthquake resistance of a building. A wide range of possible score is available and accurate determination is necessary. Occasionally, a building is an obvious combination of building types, either in different plan directions, or over the height of the building. When the building appears to be a combination of building types, the screener will need to record separate scores. This procedure can also be used when an inspector cannot determine that a building more closely resembles one type more than another. Speaker Notes

Score Modifiers Height Mid rise (4-7 stories) High rise (>7 stories) Vertical irregularity Plan irregularity Pre-code Post benchmark Soil type Slide 15 – Score Modifiers Determination of the basic building type leads to the basic score, which is then adjusted by the presence of these score modifiers. The number of score modifiers presented in the second edition is less than that presented in the first edition of the RVS guidelines. Two of the score modifiers are related to the height of the building. These height factors are mutually exclusive, that is only one or the other could be chosen if applicable. Two of the factors relate to irregularities. Buildings could have either or both types of irregularities. Two of the factors relate to the applicable building code. These factors are also mutually exclusive since a building could be classified as Pre-code or Post benchmark design code applicable to the design. The final factor relates to the type of soil on which the building is founded. These factors will be described in detail later in the presentation. Speaker Notes

Structural Scores and Modifiers
FEMA Nonstructural Earthquake Hazard Mitigation Training Structural Scores and Modifiers Building Type Basic Score Slide 16 – Structural Scores and Modifiers This slide shows the array of structural scores and score modifiers from one of the data collection forms. There is a column of modifiers for each building type, headed by the basic score. Below are the numbers to be subtracted or added for each applicable score modifier. The resulting final score permits an estimate of the building’s earthquake vulnerability. A high final score indicates that the seismic hazard associated with the building is low. A low score denotes probable poor seismic performance, and that the building should be reviewed in detail by a professional engineer experienced in seismic design. Generally, a final score of 2 is used as a criterion to differentiate between probable good and probable poor performance. Buildings with final scores less than two may not meet acceptable seismic performance and should be investigated further. Normally, only one column of building type, basic score, and modifiers will be used for each building. In those instances where a building contains two structural systems, then both relevant columns should be scored. If the building type cannot be determined, the columns for possible building types should be scored. The lowest score is the final score to be reported. Score Modifiers Speaker Notes

Final Score Calculation
FEMA Nonstructural Earthquake Hazard Mitigation Training Final Score Calculation Basic Score Mid Rise Vertical Irregularity Soil Type C Final Score 2.8 Slide 17 – Final Score Calculation Consider an example of the building in a region of low seismicity to demonstrate the method used to fill out the scoring portion of the RVS form. The building is identified as a steel braced-frame building, which is denoted as S2 (BR). The inspection reveals two score modifiers apply: the building is a mid-rise (4 to 7 stories high) and has a vertical irregularity. From information gathered before the inspection, the soil at this location is determined to be type C. The data collection form for Low Seismicity is chosen and the basic score in the S2 (BR) column is circled. The numbers in the S2 column are circled that correspond to mid rise, vertical irregularity, and soil type C. The basic score and the score modifiers are summed to obtain the final score, which is = 2.8. Determining professionally whether a building has adequate earthquake resistance is not this simple and requires an engineer experienced in seismic design to make the final determination. These procedures should help in inspecting buildings. The results of this screening will also provide a relative ranking of buildings. In many cases buildings scoring higher than 2, such as this one, can be eliminated from further consideration, and will not typically require further detailed review by a professional engineer. Speaker Notes

Seismic Hazards and Performance Levels
FEMA Nonstructural Earthquake Hazard Mitigation Training Seismic Hazards and Performance Levels Seismic Hazards Probabilistic (Return period or probability of exceedence) Deterministic Seismic Performance Levels Collapse Prevention Life Safety Immediate Occupancy Operational Slide 26 – Seismic Hazard and Performance Levels Seismic design of buildings considers two criteria: the seismic hazard being considered and the expected seismic performance level. Seismic design is a combination of these two factors. Seismic hazard describes the earthquake ground shaking that is expected. This can be represented either as a probabilistic hazard or a deterministic hazard. A probabilistic hazard presents the earthquake shaking, considering all possible sources, in terms of average expected return period or probability of being exceeded in a given time period. Most building code use a probabilistic method of determining seismic hazards. Typically, the seismic hazard that is used is one based on an average return period of 475 years, which corresponds to a 10 percent chance of being exceeded in 50 years. Another method of assigning a seismic hazard is a deterministic assessment in which the maximum earthquake from a given source is considered. The second part of the criteria is the seismic performance level. For a given earthquake hazard, the seismic design can vary depending on the anticipated performance of the building to the given hazard. In other FEMA documents, four discrete performance levels have been defined: Collapse Prevention, Life Safety, Immediate Occupancy, and Operational. Collapse Prevention represents lesser performance since the intent is only to prevent global collapse of the structure. Operational performance, on the other hand, is intended to allow the building to remain continually operational during and after an earthquake. Most building codes consider Life Safety as the expected performance. Speaker Notes

Data Collection Form Building Types
FEMA Nonstructural Earthquake Hazard Mitigation Training Data Collection Form Building Types Wood Light wood frame (W1) Large wood frame (W2) Steel Steel moment frame (S1) Steel braced frame (S2) Light metal building (S3) Steel frame with concrete shear walls (S4) Steel frame with URM infill (S5) Slide 27 – Building Types This next series of slides presents the standard Building Types as used on the Data Collection Form. The building types are generally described by the primary structural material used in the building and by the type of lateral force resisting system. These building types will be described in detail in the following slides. This slide and the next slide provide a list of the building types that will be described. The first material is wood. There are two wood building types: light wood frame construction (W1) and large wood frame construction (W2). Wood buildings represent the largest number of buildings nationally. The next material is steel. There are five steel buildings types: steel moment frames (S1), steel braced frames (S2), light metal frame buildings (S3), steel frames with concrete shear walls (S4), and steel frames with unreinforced masonry infill walls (S5). Speaker Notes

Data Collection Form Building Types
FEMA Nonstructural Earthquake Hazard Mitigation Training Data Collection Form Building Types Concrete Concrete moment frame (C1) Concrete shear wall (C2) Concrete frame with URM infill (C3) Tilt-up concrete (PC1) Precast concrete frame (PC2) Masonry Reinforced masonry with flexible diaphragm (RM1) Reinforced masonry with rigid diaphragm (RM2) Unreinforced masonry (URM) Slide 28 – Building Types (Continued) This is a continuation of the previous slide that lists the basic building types. The next group of building types is concrete. The concrete building types are further divided into those that are constructed of cast-in-place concrete and those constructed of precast concrete. The first three types listed are cast-in-place concrete: concrete moment frames (C2), concrete shear wall (S2), and concrete frame with unreinforced masonry infill (C3). The next two types are precast concrete: tilt-up concrete wall buildings (PC1) and precast concrete frame buildings (PC2). The final building types are those constructed of masonry. These are also further divided into those constructed of reinforced masonry and unreinforced masonry. The two types of reinforced masonry are reinforced masonry wall buildings with flexible diaphragms (RM1), and reinforced masonry wall buildings with rigid diaphragms (RM2). The final type is the unreinforced masonry wall building (URM). Speaker Notes

Steel Moment Frame (S1) Column Slab Welded or Bolted Shear Connection Slide 34 – Steel Moment Frame (S1) Steel rectangular moment-resisting frame buildings, often called moment frames, have vertical columns and horizontal girders of steel H-shaped sections. The floors, whatever their detail, deliver the weight of the building contents to the beams and girders. The floors are often constructed with a concrete slab, but can be constructed with wood frame floors or metal deck roofs. The girders and columns support the total weight of the building. The girders and columns are rigidly connected together into rectangular frames, usually by welding the top and bottom of the girders to the columns. The vertical web of the girder is attached with a bolted or welded connection to transfer the vertical shear from the girder to the column. Horizontal earthquake forces are resisted by the strength and ductility of the column/girder joints and the bending strength of the columns and girders. Girder or Beam Welded Moment Connection Speaker Notes

S1 Example Slide 35 – S1 Example This photo shows an example of a steel moment frame building. This example is rather unusual in that the steel girders and columns on the exterior of the building are visible. Typically, the steel members are encased in fireproofing material and thus are not visible. Because of the fireproofing, the steel columns typically have architectural finishes around them to improve the appearance. The steel beams and girders are usually hidden from view by suspended ceilings. Interior columns in two- to five-story steel-frame buildings are often 10 inches to 14 inches square inside a gypsum board enclosure. In contract, interior columns in concrete-framed buildings are almost always larger than this. Tapping on the interior column surface can indicate if it is solid concrete or a gypsum board-enclosed steel column. If access to the building is possible, raise a suspended ceiling tile and look for the H-shaped steel framing members and corrugated flooring spans above. These members will likely be coated with sprayed-on fireproofing. Speaker Notes

S1 Performance Crack weld at bottom flange of the girder to column flange moment connection Slide 36 – S1 Performance Prior to the 1994 Northridge earthquake, steel moment frame buildings were considered to provide superior seismic resistance. Following that earthquake, engineers discovered buildings that experienced earthquake damage to the welded flange connections. There were several different types of damage associated with the brittle and premature fracture of the bottom flange of the girder to column connections as shown in this slide. After extensive research, engineers concluded that a variety of factors contributed to the failures, including poor weld quality, weld material that did not have sufficient toughness, and joint details that created excessive stresses on the welds. The reports and recommendations that were developed from this research are available from FEMA in several volumes: FEMA 350, 351, 352, and 353. The results of these studies were considered in developing the basic scores for steel moment frame buildings in the second edition of FEMA 154. Speaker Notes

S2 Performance Tube Steel Brace Fractured Due to Buckling Slide 39 – S2 Performance Steel braced frames can experience a number of different types of earthquake damage. The damage is generally located in the brace and usually near the connections at the ends of the brace. Damage at the middle of the brace can also occur as the brace buckles due to compression forces on the brace. As the brace buckles, the ends of the brace rotate causing considerable stresses near the ends of the brace or connections. This picture shows damage to the brace near the connection where the steel tube has fractured. The thickness of the wall of the tube affects its ability to undergo repeated cycling of forces. Newer building codes have stricter requirements for the bracing members to avoid this type of brittle behavior of the braces. Speaker Notes

S4 Performance Cracked Concrete Wall at Interior Elevator Core Slide 45 – S4 Performance In steel frame buildings with concrete shear walls, the concrete walls are stiff relative to the steel frame so the concrete walls will typically resist most of the lateral earthquake loads. After the forces on the concrete walls causes the shear walls to reach their yield strength, the walls will soften and the steel frame may start resisting more of the earthquake forces. This slide shows a typical are of damage in steel frame buildings with concrete shear walls. As shown two slides before, the shear walls are often located at elevators and stairwells. The concrete walls often have door openings that reduce the cross-sectional area of the wall and can concentrate the damage in the wall sections adjacent to the openings. Speaker Notes

Steel Frame with URM Infill (S5)
FEMA Nonstructural Earthquake Hazard Mitigation Training Steel Frame with URM Infill (S5) Ledger for Exterior Wythe 3-Wythe Brick Infill Wall Steel Frame Slide 46 – Steel Frame with URM Infill (S5) The next building type has a steel frame that is infilled with unreinforced masonry. Usually, the masonry is multiple wythes of brick, although concrete block masonry can also be used. This type of construction is generally older buildings built in the first half of the 20th century. The masonry is usually only provided on the exterior walls and these walls provide the primary lateral force resistance for the building. This slide shows a schematic diagram of the typical construction of steel frame buildings with URM infill. The steel floor frame members supports either a wood frame floor or a concrete floor. The steel beams along the exterior of the building are not constructed in line with exterior columns. This is done so that some of the wythes of brick can be directly supported on the beam, which runs continuous along the exterior face of the building. The exterior wythe of masonry is generally supported on a ledger plate that may be attached to the steel beam. The ledger plate is usually provided at each floor so it supports the gravity load of one story of masonry. The masonry may partially or fully encase the columns. When fully encased, the masonry is usually intended to provide fire protection for the steel. Wood Framing Speaker Notes

S5 Example Slide 47 – S5 Example This slide shows an example of a steel frame building with masonry infill. This building has an exterior wythe of masonry composed of sandstone. Behind the sandstone are layers of brick masonry used as backing for the sandstone. Although the sandstone is used primarily for aesthetic purposes, the thickness and stiffness of the sandstone can attract a considerable amount of the lateral seismic force. The age of the building is a good indicator of the possibility that it is constructed as a steel frame with URM infill. These buildings are generally mid-rise to high-rise buildings constructed in the early 1900’s. Buildings that are newer that have masonry on the exterior walls may have concrete shear walls, steel braced frames, or steel moment frames. An indication of the presence of a steel moment frame building would be if the exterior masonry has horizontal joints that are filled with caulk instead of mortar. The caulking would be an indication that the design is allowing the building to move horizontally without the masonry being allowed to resist the lateral forces, which would indicate that the building type is not steel frame with URM infill. Speaker Notes

S5 Performance Slide 48 – S5 Performance This slide contains two pictures of the same building that was damaged in the Loma Prieta earthquake. The picture on the left was taken shortly after the earthquake. The picture on the right was taken later after the masonry on the end of the building was removed for repairs and strengthening. In the picture on the right, there is evidence of diagonal X-shaped cracking in several pier sections of the wall. These diagonal X cracks are due to shear forces being resisted by the wall in each direction. The picture on the left also shows damage along the corner of the building due to differential movement of the two sides of the building. Also seen in this picture is section of the wall in which the exterior wythe of brick has fallen off the building. The outer wythe of masonry is usually the most vulnerable to damage since it is typically not integrally connected to the inner wythes of brick and may only be anchored by widely spaced steel ties. These ties can often be deteriorated due to corrosion or the bond of the ties to the masonry may be deficient due to deterioration of the mortar as a result of long-term moisture exposure. Speaker Notes

Concrete Moment Frame (C1)
FEMA Nonstructural Earthquake Hazard Mitigation Training Concrete Moment Frame (C1) Infill Wall Curtain wall Slide 49 – Concrete Moment Frame (C1) In reinforced concrete construction, steel reinforcing bars are embedded in the concrete during construction. The resulting material can be effectively use in structural framing to resist tension, compression, and shear forces. There are five reinforced concrete building types: concrete moment-resisting frames (as illustrated in this slide), concrete shear wall buildings, concrete frames with unreinforced masonry infill walls (as indicated by the infill wall shown above), concrete tilt-up wall buildings, and precast concrete frame buildings. The concrete moment frame building has curtain walls outside of the plane of the concrete frame instead of infill walls within the concrete frame. The concrete moment frame has vertical columns and horizontal girders cast together to form rectangular concrete frames, as shown here. In addition to the illustrated floor slabs, the slab may itself include the spanning function of girders; in these buildings the capitals at the column-to-slab connection will be visible above the suspended ceiling. Speaker Notes

C1 Example Slide 50 – C1 Example This building has exterior concrete frames that are visible without being enclosed. The frames have glass windows within the frames that do not provide any stiffness as would a masonry infill wall. The concern with this type of construction is that the glass curtain walls be built to allow the concrete frame to deform without causing the windows to be damaged. Speaker Notes

C1 Performance Shear Cracks in Columns Slide 51 – C1 Performance Extensive earthquake-induced deformations of the reinforced concrete columns are visible in this nonductile concrete moment-frame building. Most concrete moment frame buildings in the low seismicity areas and most of those built before the 1976 Uniform Building Code in the high seismicity areas have nonductile frames. They have a limited capacity to resist large earthquake forces, and when deformed the nonductile concrete moment frames have been badly damaged and lost their strength. Nonductile behavior results from the following detailed characteristics: wide spacing between, girders that are stronger than the columns, ties in the columns and girders, main bar splices in the same location, insufficient shear reinforcement, insufficient tie anchorage, lack of continuous beam reinforcement through joints with columns, and inadequate reinforcing in joints. The relative flexibility of the structure, compared with a shear wall structure, creates the opportunity for nonstructural damage and pounding against adjacent buildings. Speaker Notes

Concrete Shear Wall (C2)
FEMA Nonstructural Earthquake Hazard Mitigation Training Concrete Shear Wall (C2) Slide 52 – Concrete Shear Wall (C2) In the concrete shear wall building, cast-in-place reinforced concrete walls support the building weight and also resist earthquake forces. There are also interior concrete beams and columns that support the building weight, but do not contribute significantly in resisting earthquake forces. Speaker Notes

C2 Example Slide 53 – C2 Example This is a typical older concrete shear wall building. Although it has a regular window pattern, the visible wall of this building does not show the rectangular grid pattern of large windows, slender piers, and shallow spandrels that is typical of a frame building. This is the front wall of the building that is featured in the first example towards the end of this presentation. Note the setback above the fourth floor that is later considered as a vertical irregularity. Speaker Notes

C2 Performance Shear and Bending Cracks in Shear Walls Repaired by Epoxy Injection Slide 54 – C2 Performance Shear cracking and distress can occur in the piers between adjacent windows and boundaries during seismic events, as shown here. Cracking can also occur due to flexural or bending stress in tall or narrow walls. In this example there are diagonal cracks due to shear stresses and cracks that are more horizontal at the ends of the walls due to bending. The cracks have been repaired by epoxy injection, which is visible along the cracks. Shear walls can fail in other ways: Shear failures can occur at horizontal construction joints in walls. Shear cracks can occur in the spandrel beams between walls, also referred to as coupling beams. Speaker Notes

Concrete Frame with URM Infill (C3)
FEMA Nonstructural Earthquake Hazard Mitigation Training Concrete Frame with URM Infill (C3) Concrete Frame Brick Infill Slide 55 – Concrete Frame with URM Infill (C3) Older concrete frame buildings may have unreinforced masonry walls infilling the frame. The infill walls provide the primary lateral force resistance for the building because the walls are very stiff relative to the concrete frame. The concrete frames in older buildings do not have the ductile detailing to allow the frames to undergo large deformations that can occur during strong ground shaking. Typically, the unreinforced masonry used as infill walls is clay brick masonry, but other types of masonry can also be used, such as hollow clay tile, and unreinforced concrete blocks. The infill walls are usually located along the perimeter of the building, but there can be infill walls around stairwells. Speaker Notes

C3 Example Slide 56 – C3 Example This an example of a concrete frame with URM infill exterior walls. The concrete frame and infill walls are visible and form a regular grid pattern. The infill walls and concrete frames can often be seen on the sides and back of the building. On the front of the building, an exterior façade may hide the concrete frame. As seen in this example, some of the infill panels may be solid infill, while others may have a variety of openings for windows. The behavior of the building can be influenced by the openings in the infill walls. Speaker Notes

C3 Performance X-Cracks in Infill Panels Slide 57 – C3 Performance This slides shows an example of a concrete frame with URM infill that was damaged in the 1964 Alaska earthquake. The URM piers between the window openings developed large X-cracks due to shear stresses in the wall. The lack of reinforcement in the walls caused the cracks to open up wide and pieces of the masonry to spall off. The other effect that can be seen is the greater amount of damage at the lower two floors of the building compared to the upper floors. This demonstrates that the shear stresses accumulate down to the base of the building. Speaker Notes

Tilt-up Concrete (PC1) Slide 58 – Tilt-Up Concrete (PC1) The concrete tilt-up wall is often used for large one- or two-story industrial or warehouse buildings. The reinforced concrete walls, which are cast as panels on the building floor and then titled up into place, resist both gravity loads (vertical) and earthquake forces (in their own plane). In the slide, three panels are laid out on the surrounding ground, to pictorially open up the building. Pilasters are thicker sections of the wall at the panel intersections and are often used to support roof girders. The walls of these buildings generally have panels of regular width. Unlike shear wall buildings, formwork marks will not show on the wall surface. These buildings usually have wood- or steel-frame elevated floor and roofs. Speaker Notes

PC1 Performance Slide 61 – PC1 Performance This example shows the consequence of the cross-grain bending failure of the ledger. Once the ledger has failed, it can no longer support the weight of the exterior bay of the roof. As can be seen on the right, failure of the ledger can then cause the roof to collapse. The roof provides lateral stability for the concrete tilt-up walls. As seen in the foreground, when the roof starts to collapse, the tilt-up wall panels can loose their stability and fall. Speaker Notes

PC2 Performance Precast Connections Failed Undamaged Shear Wall Slide 64 – PC2 Performance Precast concrete buildings are vulnerable to poor design details associated with the precast elements. 1.Poorly designed connections between prefabricated elements can fail, as has occurred here. Inadequate connections are difficult to identify without the building plans. 2.Accumulated stresses can result from shrinkage and creep and due to stresses incurred during transportation. It is possible to identify the resulting cracks. 3.Loss of vertical support can occur from inadequate bearing area and insufficient connection between floor elements and columns. 4.Corrosion of metal connectors between prefabricated elements will cause visible rust stains. In this example from the 1994 Northridge earthquake, failure of the precast connections occurred prematurely, prior to the shear wall experiencing any significant damage. Speaker Notes

Unreinforced Masonry (URM)
FEMA Nonstructural Earthquake Hazard Mitigation Training Unreinforced Masonry (URM) Slide 73 – Unreinforced Masonry (URM) Unreinforced masonry, often referred to as “URM”, includes both unreinforced brick bearing wall and unreinforced concrete block bearing wall buildings. There is little or no embedded steel reinforcement in the masonry. Walls that do not bear vertical loads are considered as buildings with infill walls. The unreinforced masonry structural walls support the building weight and resists limited earthquake forces in their own plane. Many unreinforced masonry brick bearing wall buildings in the United States are more than 100 years old. The masonry walls are constructed with multiple wythes, or thicknesses, of standard bricks. There are usually two wythes of brick at the parapet, and a wythe is added below each roof or floor level. Often there are shallow arches over the door and window openings. The framing for the floors and roof, whether of wood, steel, or concrete is supported by the walls. This building type is usually four stories or less, has thick walls with visible header bricks, which are discussed in the next slide, and relatively small openings for doors and windows. Speaker Notes

URM Bearing Walls Header Course Slide 74 – URM Bearing Walls An unreinforced brick bearing wall can often be recognized by a row of header bricks laid about every sixth row or course. These are bricks laid with the short end flush with the wall face, as shown here. The header course ties two wythes together for limited increase in stability. There is no path for vertical reinforcement if there are header courses. Unreinforced masonry infill walls, filling in between steel or concrete frame members, are not load bearing. They may or may not have header courses. In some locations, the use of header bricks was not common practice. Unreinforced brick veneer has no header course. In summary, rows of header bricks imply unreinforced masonry. The absence of header bricks implies three possibilities: a reinforced walls with steel bars, concrete grout, and individual ties at about 16 inches on center each way; a veneer over a concrete steel, or wood frame or concrete or masonry wall; or, rarely, in some locations, a URM bearing wall. Speaker Notes

URM Example Slide 75 – URM Example This slide shows an example of an unreinforced masonry bearing wall building. There are several features visible that help distinguish this as a URM building. The architectural style is indicative of its age. The shallow arches over the door and window openings is indicative of older brick masonry construction, which is more likely to be unreinforced. Close examination of the exterior wall shows a regular pattern of header bricks, although this wall does not have distinct header course as is more typical. The small size of the window openings is another indication that the walls are unreinforced masonry bearing walls. Speaker Notes

URM Performance Out-of-Plane Wall Failure Slide 76 – URM Performance In an unreinforced masonry building, the exterior walls are commonly extended upwards above the roof line to form a parapet – a nonstructural and vulnerable feature. In an earthquake, these parapets often break off, creating a hazard below. If they do not break off, they add weight, and increase the earthquake forces acting on the wall at the roof line. This can cause the wall to detach from the roof, as shown here, if there are poor horizontal restraints at the floor or roof, and lead to collapse, as shown here. The floor to wall connections of older URM construction typically very weak compared to the horizontal earthquake forces due to the inherent weakness of the masonry wall, the weakness of the connection to the floor framing, and the wide spacing between such connections. Other vulnerabilities of URM buildings, up to 3 or 4 stories in height, include low shear strength of the lime mortar used in older buildings and out-of-plane bending of the walls that are tall and thin relative to their height. Speaker Notes

Multiple or Unknown Building Types
FEMA Nonstructural Earthquake Hazard Mitigation Training Multiple or Unknown Building Types Procedure Eliminate building types Use interior inspection and drawing review, if possible Evaluate all probable building types Record lowest score Slide 79 – Multiple or Unknown Building Types For many buildings, it may not be possible to determine an applicable building type. Some buildings may be constructed with multiple building types. This can occur either when a building is constructed on top of another structure or when a building has a different structural system in each direction. Other buildings may have exterior cladding or other architectural features that hide the structural system. Others have additions in a different building type. The following procedure is recommended when a building has an unknown building type: Using visual observations, eliminate as many building types as possible Conduct and interior survey and/or review structural or architectural drawings for the building, if available From the remaining building types, evaluate the RVS score for each probable building type Record the lowest score from each of the probable building types When a building has multiple building types, each building type should be scored separately and the lowest score is recorded. Speaker Notes

Recording Building Type and Score
FEMA Nonstructural Earthquake Hazard Mitigation Training Recording Building Type and Score Seismicity Building Type Identifier W2 S1 (MRF) S2 (BR) Abbreviation Slide 80 – Recording Building Type and Score We now turn our attention to building scores and performance modifiers. When the seismicity of the building site has been identified and the correct data collection form selected, the building information can be recorded. The inspector has determined the building type or possible types for the building, and can circle its identifier and abbreviation: S1 (MRF) For example, on the form. Below the building type abbreviation is the basic score for the building, which also should be circled. 3.8 2.8 3.0 Basic Score Speaker Notes

Basic Structural Hazard Scores
FEMA Nonstructural Earthquake Hazard Mitigation Training Basic Structural Hazard Scores Building Type Low Seismicity Moderate Seismicity High Seismicity W1 S1 S3 PC1 URM Slide 81 – Basic Structural Hazard Scores This table shows the building type basic scores by seismicity. Several patterns are evident. Some building types have consistently higher scores; wood frame buildings, for example. Most buildings score higher in low seismicity areas, as expected. The variation in score between low and high seismicity is different for different building types. Unreinforced masonry (URM), as well as steel frame with unreinforced masonry infill (S5), and concrete frame with unreinforced masonry infill (C3), cannot pass the screening test in high seismicity areas when only the basic score is considered. Speaker Notes

Score Modifiers Mid Rise (4-7 Stories) High Rise (>7 Stories) Vertical Irregularity Plan Irregularity Pre-Code Post Benchmark Soil Type C Soil Type D Soil Type E Slide 82 – Score Modifiers After determining the building type, the next step is to determine if its basic score might be modified. The score modifiers are listed here and their location on the form is indicated. These modifiers have varying values depending on the building type. The score modifiers are added or subtracted to the basic score. The modifiers are listed below and are described in the next series of slides. Their identification is crucial if the building is scoring low. Mid rise buildings – those that are four to seven stories high High rise buildings – those that are greater than seven stories high Buildings with vertical irregularities Buildings with plan irregularities Pre-code Buildings – those designed and constructed before the adoption and enforcement of seismic building codes Post-benchmark buildings – those designed and constructed using modern seismic building codes There are also three modifiers that relate to the soil at the building site. If the soil at the site corresponds to either type C, D, or E, then the appropriate modifier for that soil type is applied. Speaker Notes

Vertical Irregularity
FEMA Nonstructural Earthquake Hazard Mitigation Training Vertical Irregularity Setbacks Hillside Soft Story Short Column Setbacks Hillside Slide 85 – Vertical Irregularity The next modifier is vertical irregularity. Vertical irregularities in all building types refers to irregular shapes or features, such as discontinuous columns, setbacks, and large openings that can make a building vulnerable to earthquake shaking. The intent is to describe a condition where the irregularity produces a negative effect on the performance of a building by concentrating the damage at the location of the irregularity. There are four types of vertical irregularities depicted in this slide: Setbacks Hillside Short columns Soft story The score modifiers for vertical irregularity is always negative, which reduces the building’s score. The slides that follow provide examples of each of these vertical irregularities. Short Column Soft Story Speaker Notes

Setback Example Slide 86 – Setback Example This photo shows an example of a building with multiple setbacks. Setbacks can be a detriment to seismic performance since damage can be concentrated at the floor where the setbacks occur. The following are some considerations for applying the vertical irregularity modifier for a building with a setback: The presence of a penthouse on the roof of a building should not necessarily be considered a setback since the penthouse is typically small compared to the typical floor and may not be considered as an integral part of the lateral force resisting system of the building Setbacks in the lateral force resisting system can occur even though the dimensions of the building do not change from floor to floor, as when the amount of shear wall decreases substantially on higher floors or the number of braced frame or moment frame bays change. These conditions often require review of the building plans to identify. Speaker Notes

Soft Story Example Slide 88 – Soft Story Example Quite often, buildings have a larger number of openings in the lowest story compared to the upper story. This can be for garage doors, shops, or for other architectural reasons. As a result, the exterior walls of the building are discontinuous and do not extend continuously over the entire height of the building. In a building that relies on the stiffness of the exterior walls for resistance to lateral forces, the discontinuity causes one story of the building to be soft relative to the other stories. Damage is often concentrated at these soft stories, particularly when the soft story occurs at the base of the building. However, soft stories can also occur at other stories if there are abrupt changes in stiffness. This slide shows an example of damage to s soft story apartment building in the marina district of San Francisco caused by the 1989 Loma Prieta earthquake. The garage doors at the first story, along with the open entrance area, caused the first story to have much less stiffness and strength than the upper floors of the building. This caused the damage to be concentrated at this story. Not the there is no visible damage to the upper stories of the building. Often, a steel moment frame (S1) or concrete moment frame (C1) building will have less curtain wall enclosure at the ground floor than at the upper floors. As there curtain walls are not structural elements and do not affect the frame stiffness, the soft story modifier should not apply. Speaker Notes

Short Columns Example Slide 89 – Short Columns Example The short column modifier is applied to concrete or masonry buildings that have many columns that are considerably shorter than the floor-to-floor height of the building. Often this feature is caused by architectural elements that impede the lateral movement of the structural framing. This occurs, as shown here, by a partial height exterior infill masonry wall restraining the lower portion of the columns. The short column failure pictured here occurred during the 1994 Northridge earthquake. When earthquake forces are applied to buildings with short columns, they are much more likely to fail in shear, with x-cracks, rather than failing in bending with hinges at top and bottom of the column. The shear x-crack failure is more brittle than the hinging bending failure and will more likely cause the column to lose its vertical load-carrying capacity. Concrete columns, particularly in older concrete construction, do not have sufficient horizontal confinement reinforcing to allow the columns to respond in a ductile manner to shear forces. Speaker Notes

Plan Irregularity L-Shaped T-Shaped U-Shaped Slide 90 – Plan Irregularity Building that have irregular plan with shapes such as L, T, U, or open-courtyard shapes tend to have less earthquake resistance than those with simple rectangular plan shapes. Each of the wings tries to move independently during ground shaking. The damage tends to be concentrated at inside corners, referred to as re-entrant corners, when the design seldom considers the earthquake demand. All building types are susceptible. In this slide, several typical examples of plan irregularities are shown. The arrows point to the location of the re-entrant corner or other locations where the damage is likely to be concentrated. Weak Link Between Larger Building Plan Areas Large Opening Speaker Notes

Plan Irregularity Example
FEMA Nonstructural Earthquake Hazard Mitigation Training Plan Irregularity Example Slide 91 – Plan Irregularity Example This shows an example of a building with plan irregularities. This residential building has multiple wings off the main section. The re-entrant corners created by the wings presents areas of vulnerabilities. When the wing motions are phased so that they alternately move towards each other and apart, the stresses in the inside corner are high. Speaker Notes

Pre-Code Constructed prior to initial adoption and enforcement of seismic codes Applies to Moderate and High seismic zones Default year is 1941 (California) Slide 92 – Pre-Code The design criteria for buildings against earthquake forces has changed considerably over the last century. Buildings constructed before the adoption and enforcement of seismic design requirements are less likely to contain the necessary strength and detailing required to resist significant earthquake shaking. The Pre-Code modifier should be used when the design and construction of the building precedes the year in which significant seismic design provisions were first considered. For most building types, 1941 is the default year for assessing the need for the Pre-Code modifier. For tilt-up buildings (PC1), the default year is 1973. This modifier only applies to buildings in moderate and high seismic zones due to the method used to calculate the basic structural hazard scores. Speaker Notes

Post Benchmark Years Building Type W1 W2 S1 S2 S3 / S5 S4 BOCA SBCC UBC BD BD Slide 93 – Post Benchmark Years The adoption and enforcement of the seismic requirements of the building codes varies amongst localities. Codes include seismic requirements if later that the dates tabulated here for the BOCA National Building Code, the SBCC Southern Building Code, and the ICBO Uniform Building Code (UBC). The BOCA National Building Code is used in the northeastern US, the SBBC Southern Building Code is generally used in the southeastern US, and the UBC is generally in use in the western US. Find out whether the local building department has adopted current significant seismic requirements into its building code. If so, the year these seismic requirements were adopted and enforced is the benchmark year for the jurisdiction. If the inspected building was designed and built prior to that year, it was probably not built in accordance with a seismic code. Generally speaking, significant seismic requirements were introduced into the UBC in the mid-1970’s and into the other model codes at later dates. This table shows the benchmark years for half of the building types. For steel moment frame buildings, the local building department should be contacted to determine when the seismic design provisions incorporated seismic details. There is no benchmark year for light metal buildings (S3), or steel frame buildings with URM infill (S5). None None None Note: BD - Contact Local Building Department Speaker Notes

Post Benchmark (Cont.) Building Type C1 / C2 C3 PC1 / RM1 PC2 RM2 URM BOCA SBCC UBC None None None None None None None None Slide 94 – Post benchmark Years (Continued) This is a continuation of the previous slide showing the benchmark years for the remaining building types. There is no benchmark year for concrete frames with URM infill (C3), or precast concrete frames (PC2), so there is no need to search for it at the local jurisdiction building department. With the exception of buildings designed using the UBC, there is no benchmark year for tilt-up buildings (PC1), reinforced masonry buildings (RM1), or unreinforced masonry buildings, URM. Note that the benchmark year for the BOCA and SBBC codes for most building types is much later than the UBC for the same building types. This is due to the BOCA and SBCC codes late adoption of modern seismic design requirements. None None Speaker Notes

Soil Type Type A - hard rock Type B - rock Type C - Soft rock and very dense soil Type D - Stiff soil Type E - Soft soil Type F - Poor soil Slide 95 – Soil Type The inspection should include an assessment of the site conditions. There are screening procedures to identify less desirable sites. The ground shaking intensity at the building site will be influenced by the type of soil. Deeper soft soils increase both the strength and the duration of earthquake shaking and increase vulnerability. Some soft soils may also be prone to liquefaction, settlement, or subsidence. Six soil types are defined: Type A is defined as hard rock, which is generally only found in the eastern and midwestern US Type B is defined as rock Type C is soft rock or very dense soil Type D is stiff soil Type E is soft soil Type F is poor soil Soft soils are found in marshlands and along the margins of bays or lakes. They may also be deposits under former bays or lakes. City, county, state, or US Geological Survey geologists can assist in identifying areas with soft soils. Types C, D, and E soils require performance modifiers. If there is no basis for classifying the soil type, a soil type E should be assumed. However, for one-story or two-story buildings with a roof height equal to or less than 25 feet, a class D soil type may be assumed when site conditions are not known. There is no score modifier for Type F soil, which is used to describe conditions such as liquefiable soils, highly organic clays or very deep deposits of clay. Buildings on these soil types cannot be effectively screened using the RVS procedure since the behavior of the building is significantly dependant on the behavior of the soil. A geotechnical engineer is required to confirm the presence of Type F soil. Speaker Notes

Soil Type Map Slide 96 – Soil Type Map This map of the San Francisco Bay Area illustrates the variation of soil types. There are four different types of soil shown here described previously. The green areas depict rock type soils, type B. The yellow areas depict dense soil, type C. The light orange areas depict stiff soil, type D. The dark areas depict soft soils, type E. Areas of soft soil have experienced more damaging ground shaking. In the Loma Prieta earthquake, for example, buildings in the soft soils area of the Marina district and South of Market district of San Francisco experienced more damage than buildings in other areas. Buildings and other structures in west Oakland also experienced significant damage. This is the location of the Cypress Freeway structure that collapsed, causing many fatalities. Speaker Notes

Occupancy Assembly Commercial Emergency Services Government Historic Industrial Office Residential School Number of Occupants 0 - 10 >1000 Slide 97 – Occupancy We now address the issues of building occupancy. The occupancy uses listed on the form are Assembly, Commercial, Emergency Services, Government, Historic, Industrial, Office, Residential, and School. Residential includes hotels and motels as well as houses and apartments. Places of public assembly are those where 300 or more people might be gathered in one room, such as theaters, performance halls, and churches. Emergency Services includes police and fire stations and hospitals. Circle the building use or uses that fits best. The occupancy load choice is 0-10, , and Circle the range that best describes the in-use occupancy of the building. The occupancy load may be used by the jurisdiction to set priorities for hazard mitigation plans. Speaker Notes

Nonstructural Falling Hazards
FEMA Nonstructural Earthquake Hazard Mitigation Training Nonstructural Falling Hazards Unreinforced Chimneys Parapets Cladding or veneer Other Appendages Equipment Slide 98 – Nonstructural Falling Hazards Nonstructural elements are defined as those parts of the building that are not part of the structural frames, walls, floors, or roof. Exterior nonstructural elements include chimneys, parapets, cornices, veneers, and overhangs. Interior nonstructural elements include suspended ceilings, equipment, large storage racks, and bookcases. These elements may be hazardous if not adequately anchored to the building. Check the box for Nonstructural Falling Hazard if the hazard is significant. Previous slides have shown veneers, parapets, and chimneys that are falling hazards. The following four slides show additional typical exterior falling hazards. Speaker Notes

Performance of Parapets
FEMA Nonstructural Earthquake Hazard Mitigation Training Performance of Parapets Slide 100 – Performance of Parapets Parapets are vertical extensions of the exterior wall above the roof creating a cantilevered element above the roof of the building. Parapets constructed of unreinforced masonry are particularly vulnerable to flexural failure due to the lack of bending strength of the unreinforced masonry. The building in this slide had a large section of the unreinforced masonry parapet fail by falling away from the building. This creates a potential life safety hazard since this occurred above the entrance to the building. In most cases, the parapet fails by falling away from the building since the flexural failure occurs below the roof level and the roof provides restraint to inward movement of the parapet. Speaker Notes

Performance of Cladding
FEMA Nonstructural Earthquake Hazard Mitigation Training Performance of Cladding Slide 101 – Performance of Cladding Brick veneer can be a falling hazard for wood framed, as well as steel or concrete frame, buildings. This wood framed building has brick veneer that was only marginally connected to the framing and is susceptible to out-of-plane failure. The exterior brick veneer is also at least as stiff in plane as the wood frame sheathing but does not have the strength to resist earthquake forces. When the building deformed in plane, the brick veneer cracked badly and became a falling hazard. This brick can also be used to identify the building type. All the brick is in running bond; no end brick courses are seen. Running bond brick walls are used as veneer in all of the concrete, steel, and wood building types, and in reinforced and unreinforced masonry wall buildings. They are sometimes used in concrete or steel infill wall buildings. In this building, close inspection reveals that no inner brick wythe is present to make it a reinforced masonry bearing wall building, and that wood framing is present to identify it as a wood frame building. Speaker Notes

Other Falling Hazards Architectural Interior ornamentation Heavy partitions Building services Mechanical equipment Electrical equipment Contents Racks and shelving Slide 103 – Other Falling Hazards In addition to the common falling hazards described previously, there are a variety of other types of falling hazards that can exist. The Data Collection Form includes a check box for other falling hazards and a space to describe the falling hazard. Falling hazards are typically nonstructural elements, those elements that are not part of the structural system for the building. Types of other falling hazards include: Architectural elements, such as interior ornamentation and heavy partitions Building services elements, such as mechanical or electrical equipment Building contents, such as tall storage racks and shelving Speaker Notes

Rapid Visual Screening Implementation
FEMA Nonstructural Earthquake Hazard Mitigation Training Rapid Visual Screening Implementation Develop budget and cost estimate Plan field survey and identify the area to be screened Choose and train screeners Review existing construction drawings Acquire and review pre-field data Select and review Data Collection Form Slide 104 – Rapid Visual Screening Implementation This slides presents the stages of the implementation of the rapid visual screening procedure. These stages are described below and discussed further in the slides to follow: Develop a budget and cost estimate for the implementation of the rapid visual screening Pre-plan the field survey and identify the area or areas to be screened Choose and train the personnel that will conduct the rapid visual screening Select the appropriate Data Collection Forms for the area and review the forms Acquire and review the pre-field data for the buildings in the area to be surveyed Review existing construction drawings for the buildings Screen the buildings using the Data Collection Form, including sketching the plan and elevation of the building If the interior of the building is accessible, survey the interior of the building to verify the building type and the presence of irregularities Photograph the building Check the field data and record the building data into a record keeping system If you have access to the interior, verify building type and irregularities Screen the building, sketch the plan and elevation Photograph the building Check the field data in the record keeping system Speaker Notes

Pre-Screening Tasks Determine seismicity region Determine key seismic code adoption dates Determine cut-off score Acquire pre-field survey building data Determine soil information Slide 105 – Pre-Screening Tasks This slide describes several of the key tasks to be completed in the screening procedure prior to the field survey. These tasks are important in accurate determination of building type. Determine the seismicity region Determine key seismic code adoption dates Determine cut-off score Acquire pre-field building data Determine soil information Speaker Notes

Field Survey Tools Binoculars for high-rise buildings Camera, preferably instant or digital Clipboard for holding Data Collection Forms Copy of the FEMA 154 Handbook The Quick Reference Guide Pen or pencil Straight edge (optional for drawing sketches) Tape or stapler, for affixing instant photos Slide 107 – Field Survey Tools The field screening of building using the RVS procedure should ideally be accomplished with a team of two persons. One member of the team should be experienced in seismic design or evaluation. The field survey should take 15 to 30 minutes per building. If interior access is available, the time may be increased to be between 30 to 60 minutes. Only a few tools are necessary to carry out the RVS screening. These are: Binoculars, if high rise buildings are being surveyed, to allow for observation of upper floors A camera, preferably an instant camera or digital camera A clipboard for holding the data collection forms A copy of the FEMA 154 handbook A copy of the Quick Reference Guide A pen or pencil for completing the form A straight edge for use in drawing sketches of the building A stapler or tape for affixing an instant photo to the Data Collection Form Speaker Notes

Data Collection Form Building Identification Sketch Photograph Falling Hazards Soil Type Occupancy Building Type Modifiers Final Score Comments Evaluation Required Slide 108 – Data Collection Form Implementation of the field inspection involves completely filling out the Data Collection Form. It is important that all of the sections of the form shown above are completed. The building identification information includes building address, name, year built, number of stories, square footage, and use. Much of this information can be obtained from the pre-field data collection sources. Note that in some cases, multiple addresses are associated with a single building. Each of the addresses should be recorded. A building sketch should ideally include a typical floor plan and an elevation. If possible, the sketch should be drawn to scale. A photograph of the building exterior can be taken using an instant photo or a digital photo. The presence of all nonstructural falling hazards should be checked. The soil type at the site should be circled. The occupancy type and count should be circled. The appropriate building type, or types, should be circled. Any score modifiers should be circled. The final score for each of the appropriate building types should be calculated. Any comments regarding the building should be recorded, such as noting features that potentially improve or detract from the expected performance of the building. The final step is to indicate whether a detailed evaluation of the building is required. Speaker Notes

Use of RVS Results Designing seismic hazard mitigation programs Ranking seismic rehabilitation needs Developing building inventories Earthquake damage and loss impact assessments Planning post-earthquake building safety evaluations Developing seismic vulnerability information Insurance rating Building ownership transfers Triggering seismic rehabilitation requirements during building remodel permitting Slide 109 – Use of RVS Results The results of the RVS survey should be recorded into a database and this data can be used for a number of purposes such as: Designing seismic hazard mitigation programs Ranking seismic rehabilitation needs Developing building inventories for earthquake damage and loss assessments or for planning post-earthquake building safety evaluations Developing seismic vulnerability information for use in insurance ratings, building ownership transfers, or triggering seismic rehabilitation requirements during building remodel permitting Speaker Notes

Example 1 Slide 111 – Example 1 Here is a photograph of the first example building. Assume that we know that it is located in Oakland, California. From the FEMA 154 maps, we determine that this is a high seismic region, we select the data collection form marked High to collect our data. Prior to the field visit, we collect other information, including the dates of adoption of key seismic codes, the cut-off score to be used in the screening, and the soil type. The pre-field data indicates that the building is located in an area considered to be Soil Type D, and that the occupancy is government, with 101 to 1000 occupants. Speaker Notes

Example 1 (Cont.) Building Type: Concrete Shear Wall C2 Slide 112 – Example 1 (Continued) The exterior is fairly continuous except for the window openings. There is not a distinct beam and column grid to the walls. The walls are of concrete and show the grain surface and width of the boards used to form the concrete. From these characteristics, we determine that its building type is C2, Concrete Shear Wall. Speaker Notes

Example 1 (Cont.) Modifiers: Mid Rise Vertical Irregularity Plan Irregularity Soil Type D Slide 113 – Example 1 (Continued) Next, we determine if any modifiers apply. The building is four stories tall and is therefore considered to be mid-rise. We remember from the previous slide, or a walk around to the right to the front of the building) that the building has a significant setback in its façade that should be considered a vertical irregularity. We also observe that there is a significant wing at the back of the building, as shown here, that gives the building a T-shaped plan. This should be considered a Plan Irregularity. As mentioned in an early slide, the soil type determined from the pre-field data is type D. Further inspection indicates that no other modifiers apply. As we make our observations, we fill in the building identification data at the top of the data collection form, draw a plan view in the area at the top left of the form, and attach a photo to the right side of the form. Speaker Notes

Example 1 Scoring Building Type C2 Basic Score Mid Rise Vertical Irreg Plan Irreg Soil Type D Final Score Slide 114 – Example 1 Scoring This shows the structural scores and modifiers from the investigation. We have begun by circling the building type, C2, SW and its basic score, 2.8. We have circled the applicable modifiers, which are Mid Rise, Vertical Irregularity, and Plan Irregularity. From information obtained during the pre-field trip data collection, we know that this building was built after the adoption of seismic building codes but before the benchmark year for concrete shear wall buildings. Thus, neither the Pre-Code not the Post-Benchmark modifiers are applicable. We also circle the soil type modifier for Soil Type D, -0.5, based on soil information obtained for the site. We have summed the column to arrive at a final score: – = 1.2. A score of 2.0 or less identifies the building as a potential seismic hazard. A further investigation by a professional engineer with seismic design experience would be necessary to determine if the building is, in fact, hazardous. 1.2 Speaker Notes

Example 1 - Completed Form
FEMA Nonstructural Earthquake Hazard Mitigation Training Example 1 - Completed Form Oakland, CA 3 Stories 4 4 Stories Office High Roof 4 Stories 4 Stories 4th Floor Addition Plan Slide 115 – Example 1 – Completed Form Here is the completed data collection form for the building. In addition to the structural scores and modifiers, the building identification information has been entered at the top of the form; a plan sketch has been drawn on the left; an instant photo has been placed at the right; the occupancy and falling hazard information has been entered in the middle of the form; comments are entered at the bottom. Based on the final score, the need for a detailed evaluation has been entered at the lower right. 1.2 Speaker Notes

FEMA Existing Buildings Program
ASCE 31 (FEMA 310) – Seismic Evaluation ASCE 41 (FEMA 356) – Seismic Rehab Guidelines FEMA – Incremental Seismic Rehabilitation of Various Occupancies FEMA 420 – Engineers Guide to Incremental Seismic Rehabilitation FEMA 547 – Techniques for Seismic Strengthening of Buildings

FEMA Nonstructural Earthquake Hazard Mitigation Training

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FEMA Nonstructural Earthquake Hazard Mitigation Training

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