Presentation on theme: "Advanced Construction Technology"— Presentation transcript:
1Advanced Construction Technology By Professor Chris Gorse & Ian Dickinson – licensed under the Creative Commons Attribution – Non-Commercial – Share Alike License
2Pad Foundations Chris Gorse and Ian Dickinson These slides should be read in conjunction with Emmitt, S. and Gorse, C. (2010) Barry’s Advanced Construction of Buildings. Oxford, Blackwell Publishing
3Pad foundations Ground beams Pads Pad foundations. More commonly used under point loads such as columns, but can be used under ground beams to transfer continuous loads. The width and depth of each pad foundation will depend on the soil conditions and building loads.
4Pad foundationLoads transferred through column to base-plate then to concrete pad foundationBase platePad foundationPad foundations are often rectangular or square and are placed to receive point loads at a central position
5Excavation for pad foundation Bolt boxes for steel columns ready to be positioned in the concrete
8Pad foundations – ground beams Point loads from columns transferred to pad foundationStable load bearing strataAny continuous loads applied through walls are transferred along reinforced concrete beams to the pad foundationGround beamPad foundation
9Pad foundation and ring beam excavation Pad foundation and ring beam excavation. String lines mark out the centre lines for the holding down bolts. The holding down bolt box will be positioned when the concrete is poured.
10Pad foundation and ground beam excavation Pad foundation and ground beam excavation. Ready to receive steel reinforcement cages and concrete
11Pad foundation, with holding-down bolts for column Pad foundation, with holding-down bolts for column. Reinforcement starter bars are evident, these will be used to tie the ground beam into the foundation.
12Reinforced pad foundation Point loads from columns transferred to pad foundationLoad from column distributed across the full area of the foundationReinforcement runs in both directionsReinforced Pad foundationExploded view showing reinforcement
13Distributing the load Large point load The reinforcement in the pad foundation adds tensile strength allowing the loads to be distributed over a larger area.As the load is distributed over a larger area the load per unit area is reduced
14Mass fill pad foundation Point loads from columns transferred to pad foundationBy excavating deeper into the ground and filling with concrete the loads of the building can be transferred to lower strata.Where the surface soil and strata is week it may be possible to excavate deeper to good load-bearing strata.
15Pad foundation and column base (prior to filling with grout)
16Base of column fastened to the pad foundation by holding down bolts Base of column fastened to the pad foundation by holding down bolts. Wedges hold the column in position until the bolts and column base is grouted. Expanding grout will be poured under and around the base plate filling all the voids and making sure the column and pad foundation make proper contact with each other.
17Steel wedge holds the steel column in the correct position
18Sand position around the column ready to receive expanding grout Sand position around the column ready to receive expanding grout. The group secures the base plate in its final position.
19DiscussionIdentify and discuss the situations where pad foundations are most likely to be used.What is the most common type of structure that would be founded on a pad foundation.
20Further information supporting these slides can be found in the following publication and websites. Emmitt, S. and Gorse, C. (2010) Barry’s Introduction to Construction of Buildings. Oxford, Blackwell PublishingEmmitt, S. and Gorse, C. (2010) Barry’s Advanced Construction of Buildings. Oxford, Blackwell PublishingVirtual Site (2010) Virtual Site at Leeds Met UniversityVirtual Site Gallery (2010) Virtual Site Gallery at Leeds Met University