CIEG 301: Structural Analysis INTRODUCTION Types of Structures Loads

Corresponding Reading Chapter 1 of textbook

What Do Structural Engineers Do? Analyze and design new structures Investigate the capacity and serviceability of existing structures Develop retrofit methods for existing structures with inadequate capacity Forensic investigations Research and development

Building Types Majority of buildings are 2 – 20 stories Taller office buildings Sports arenas Low seismic / high seismic

Bridge Types Highway Railroad Shipping Commuter Pedestrian

Design Objectives Strength Constructability Serviceability Maintainability Economy Aesthetics

Design Process Initial planning Determination of design alternatives Preliminary design of alternatives Evaluation of alternatives Design, analysis, and redesign of selected alternative Construction

Structure Types Frames Trusses Slab-on-stringer Cables Arches Surface structures Complex structures

Member Types Each of these structures is comprised of hundreds or thousands of members Some common member types Beams / Girders / stringers - flexural members – load applied perpendicular to length, moment and shear are primary forces Columns – compression members – load applied parallel to length at member ends, axial force dominates Beam-columns Tension members Compression members Tie rods – tension force only Arches Common connection types Pinned Fixed

Support Types Roller Pin Fixed

How do we design structures? Conceptual Consideration: Determine forces (and deflections) Our focus for the semester Determine capacity (and deflection limits) Focus in Structural Design next semester Require capacity is greater than forces Legal Considerations For most structures, owner specifies code e.g., AISC, PCI, AASHTO, AREMA

Loads Forces in a structure are a result of loads What types of loads do we need to consider in a civil engineering structure: Dead load: Live load: building occupants, truck traffic Environmental loads: Snow load Rain load Wind load Seismic load Bridge specific Temperature loads (expansion and contraction of restrained members) Impact Breaking force Collisions (water and land traffic) Water loads Ice

Dead Loads Self-weight of: Structural components (e.g., beams, slabs) Non-structural components (e.g., decorative façade, plywood subfloor, ceiling tiles, asphalt wearing surface) Useful Tables in textbook: Table 1-2: Densities of Typical Materials Table 1-3: Dead Loads of Typical Materials

Load Transfer and Load Distribution Consider a typical building framing plan Work from top down Determine tributary widths and tributary areas as appropriate