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Concrete
- 1. CONCRETE CONSTRUCTION “ Concrete is a plastic material susceptible to the impressions of the imagination.” Frank Lloyd Wright
- 6. Meditation Center for UNESCO Paris, France 1995 Tadao Ando, Architect “ a space of prayer for world peace” “ A rchitecture, to me , is an endless search of one’s engagement with oneself and with society From the construction of an abstract concept to its realization.” TADAO ANDO AIA Gold Medal 2003
- 7. TADAO ANDO Oyamazaki Villa Museum Yagi house
- 17. Sample collected Slump Measured Cone Removed and Concrete Allowed to ‘Slump’ Slump Cone Filled
- 18. Measuring the Slump Walls/columns 4-5 in. Beams 4-5 in. Slabs 3-4 in.
- 19. Test Cylinders Filled with a Sampling of the Concrete Mix
- 20. Test Cylinders Curing and then strength tested (upper right)
- 22. Placement Today - not too much has changed!
- 23. Concrete Bucket being Filled
- 24. Placement of a Wall with a Crane & Concrete Bucket
- 25. Placement with a Concrete Pump
- 26. Placement with a Concrete Pump Placement with a Concrete Pump
- 27. Placement with a Conveyor
- 28. Improperly Consolidated - “Honeycomb” Segregation - Mix “Separates” Results - Non-uniformity & Unsatisfactory properties Common Causes Excessive Vibration Dropping From Excessive Heights Moving Concrete Horizontally
- 30. Extensive Reinforcing Can Make Placement & Consolidation Difficult
- 31. “ Cold” Joint First lift hardened prior to the placement of the 2 nd lift
- 40. WWF – Sheet (mat)
- 42. Wall Reinforcing being secured with Wire Ties
- 43. Long Bridge Pier Requiring Reinforcing Splicing
- 54. Plastic-sheathed to prevent bonding to concrete (note the cable is lubricated)
- 55. Draped to be positioned in “Tension” area of slab
- 56. Cables can be ‘Bundled’
- 57. Cable attachment to Edge Form
- 58. Hydraulic Jacking Machine to Stress Cables
- 59. Elongated Strands after Stressing (Jacking)
- 62. Placement with a Pump
- 63. Laser-screed Often used for ‘superflat’ floors
- 64. Finishing Rotary Power Trowel (Rider - Double Blade) Finishing Rotary Power Trowel (Walk behind)
- 66. Snap ties
- 67. Ties inserted through pre-drilled holes
- 68. Clamp placed over endloop of tie
- 69. Waler placed over clamp and locked down
- 70. Vertical stiffback attached to assembly
- 71. Stiffback locked in place
- 72. Completed connection: plywood, waler, tie & stiffback
- 75. Panelized System with its Own Tires Panelized System
- 78. Gang Forms
- 85. Sonotube – Waxed Cardboard Column Form Material
- 86. Stripped Column Note the spiral formwork markings
- 91. One-Way Slab & Beam
- 92. One-Way Slab & Beam
- 99. Beam Formwork Form Beam Bottoms & Sides
- 101. Elevated Slab Sequence (cont.) Place, Consolidate, & Finish and Cure
- 104. Columns Placed & Form Support (Scaffolding) Being Erected
- 105. Form Support (Scaffolding) Being Erected
- 106. Decking Support Beams Being Erected
- 107. Plywood Decking Being Erected
- 108. Plywood Decking and Beam Sides Being Erected
- 109. Plywood Decking and Beam Sides Being Erected
- 110. Plywood Decking & Beam Sides Erected
- 111. Plywood Decking and Beam Sides Erected on a Portion
- 112. Deck Support System (Scaffolding)
- 117. Beam & Deck Reinforcing Installed
- 121. Post-Tensioning Complete and MPE Sleeves Installed
- 122. Slab Poured & Cured Stripping & Post Shores
- 123. Stripping formwork
- 124. Stripping formwork
- 125. Formwork Stripped and Reshores Installed
- 127. Lift-slab (Note the slab supports at the columns)
- 128. Tilt-Up Walls cast Horizontally & “Tilted” into Place Commonly used in Warehouse, Distribution, Retail
- 129. The following group of photos shows the tilt-up sequence used for construction of a Home Depot
- 130. Slab-on-Grade Placed
- 131. Formwork for Panels
- 132. Edge form & reinforcing installed Slab-on-Grade Placed
- 133. Opening Installed
- 134. Panels formed and reinforced
- 135. Panels Formed and Reinforced (Note the Inserts)
- 136. Inserts for Panel Braces, Steel Framing Anchorage, & Panel Lifting Weld Plate for Joist Attachment Insert for Brace Insert for Lifting Bracket
- 137. Panels Poured
- 139. Placement of Exterior Footing Panels SOG
- 140. Crane for Panel Installation
- 141. Braces Installed Prior to ‘tilting-up’ the panels
- 142. Attachment of Lifting Bracket
- 143. Panel being lifted (tilted into place)
- 144. Panel being lifted (tilted into place)
- 145. Panel being lifted (tilted into place)
- 146. Panel being lifted (tilted into place)
- 147. Panel being placed on shims set to proper elevation
- 148. Panels being braced
- 149. Panels braced
- 150. Panel grouted between footing & panel
- 151. Roof support structure anchored to panels
- 152. Subgrade prepared for panel structural connection to Slab-on-Grade
- 153. Slab-on-Grade perimeter poured to anchor the panel bottom.
- 154. Panels erected
- 157. Exposed ‘Architectural’ Concrete at the University of Iowa
- 158. Exposed ‘Architectural’ Concrete at the University of Iowa
- 159. Exposed ‘Architectural’ Concrete (Note the rough finish )
- 164. Architectural Concrete with “Bushhammered” Finish
- 165. Architectural Concrete with “Bushhammered” Finish
- 166. Simulated Stone Form Liner
- 167. Considerations / Challenges Rustication Location Form Tie Location
- 168. Considerations / Challenges Formwork Joint Formwork Blemishes
- 169. Considerations / Challenges Form Tie Holes
- 170. Considerations / Challenges Rusted Bar Supports
- 171. Patching
- 174. PRECAST STRUCTURAL & ARCHITECTURAL CONCRETE
- 177. Precast Hollowcore Planks/Decking Double Tee’s Single Tee’s
- 179. Prestressing process and finished product
- 180. Tarping process for vapor curing of hollow cure planks Parking Garage both sitecast and precast concrete
- 181. Correctional Facility in Texas
- 195. Readily available colors. But any color can be custom ordered.
- 197. Form Liners For architectural concrete surfaces A Guide Specification Form Liner "Cut Sheet" Detail
- 199. Section through control joint
- 200. Isolation joints & control joints in interior isolated slab
- 201. Section: isolated slab at load-bearing wall
- 202. Keyed construction joint in slab
- 203. Construction joint between column & footing
- 204. Horizontal construction joint in wall
- 206. Section through control joint
- 207. Isolation joints & control joints in interior isolated slab
- 208. Section: isolated slab at load-bearing wall
- 209. Keyed construction joint in slab
- 210. Construction joint between column & footing
- 211. Horizontal construction joint in wall
- 212. Beam and girders with slab floors increase spans, decrease economy
- 214. One-way joist floor viewed from below
- 215. Standard module formwork with beam reinforcement laid
- 216. Standard module pan sizes
- 217. Tapered pans, widened joist ends
- 218. Wide-module pans
- 219. Flat plate slab: light occupancies, lower ceiling height, small, square bays
- 220. Flat slab has round column and drop panels
- 221. Section through hollow core slab
- 222. Precast concrete hollow core slabs rest on site-cast concrete columns and beams
- 223. Section through double-tee floor
- 224. Double-tee units on precast inverted T-beams
- 225. Double-tee meet at column and beam
- 226. Inverted T-beam
- 228. Building separation joint: Single column, site cast
- 229. Slip joint assembly
- 230. Slip joint assembly
- 231. The End
Notes de l'éditeur
- Course Aggregate approx. 3/4 of volume Structural strength heavily dependent on MUST BE: Strong, clean Resistant to freeze-thaw Chemically stable Properly Graded - Through SIEVES For proper “packing” of materials Largest must fit between Reinforcing Generally < 3/4 of clear distance or 1/3 of slab thickness Fine Aggregate Portland Cement Water Admixtures (optional)
- Course Aggregate approx. 3/4 of volume Structural strength heavily dependent on MUST BE: Strong, clean Resistant to freeze-thaw Chemically stable Properly Graded - Through SIEVES For proper “packing” of materials Largest must fit between Reinforcing Generally < 3/4 of clear distance or 1/3 of slab thickness Fine Aggregate Portland Cement Water Admixtures (optional)
- Specified by 28 Day Compressive Strength (psi) POUNDS PER SQUARE INCH CONCRETE IN THEORY CONTINUES TO HARDEN - TYPICALL 28 STRENGTH Primarily Determined By: STRENGTH PRIMARILY DETERMINED BY Amount of Cement PROPORTION/ AMOUNT OF CEMENT Water-Cement Ratio WEIGHT OF H2O / WEIGHT OF WATER NEED MORE WATER THAN WHAT IS NEEDED FOR HYDRATION - PLACEMENT AND FINISHING TOO MUCH WATER EXTRA WATER EVAPORATES LEAVES VOIDS - REDUCE STRENGTH CAN REDUCE WATER AND STILL GET WORKABILITY WITH ADMIXTURES (AIR, WATER REDUCING AGENTS) Proper Aggregate & Gradation FINE AND COARSE AGGREGATE Strength Ranges: 2000 - 19,000+ psi COMMON - 3000, 4000, 5000, 6000psi
- No Useful Tensile Strength GREAT IN COMPRESSION - LITTLE IN TENSION MOST STRUCTURAL MEMBERS IN BOTH NEED A MATERIAL FOR TENSION Reinforcing Steel - Tensile Strength Similar Coefficient of thermal expansion EXPAND AND CONTRACT SAME AMOUNT IF NOT, BREAK BOND Chemical Compatibility WON’T REACT W/ EACH OTHER & PROTECTS STEEL FROM CORROSION Adhesion Of Concrete To Steel ADHERES WELL Theory of Steel Location “ Place reinforcing steel where the concrete is in tension” SIMPLE BEAM - IN BOTTOM MULTIPLE SPAN OVER SUPPORT @ TOP
- Reinforcing Support Chairs or bolsters WIRE OR PLASTIC SOME WITH PROTECTIVE COATINGS ON FEET - SOME MADE OF SS Properly position the steel VARIOUS HEIGHTS POSITION REINFORCING OFF FORMWORK FOR DESIGN LOCATION AND MINIMUM CONCRETE POTECTION FOR FIRE RATINGS Special Coatings Galvanized or Epoxy Coated Exposure to Salts or Sea Water
- Type of Reinforcing Grid of “wires” spaced 2-12 inches apart STEEL WIRE Specified by wire gauge and spacing Typical Use - Horizontal Surfaces ELEVATED SLABS SOG USED IN SOME WALLS Comes in Mats or Rolls MATS FOR LARGER GAUGE WIRE Advantage - Labor Savings BUT CAN’T HANDLE LARGE LOADINGS
- Location of Tension Forces Changes Midspan - Bottom in Tension At Beam Supports - Top in Tension NOTE; SLAB REINFORCING PRINCIPALS SIMILAR LIKE A LARGE/WIDE BEAM EXCEPT OFTEN ADD TEMPERATURE STEEL
- Reinforced Concrete Members AT ANY LOCATION IN THE MEMBER Part of the member in compression Part of the member in tension Over half of the concrete Not carrying any load, it’s: “ Holding” reinforcing in position & Providing protective cover NOT GETTING THE FULL / EFFECTIVE USE OF THE MEMBER
- Theory; “Place all the concrete of the member in compression” (take advantage of concrete’s compressive strength of the entire member) Advantages Increase the load carrying capacity or Reduce the member’s size
- Stressing high strength steel stands either before or after concrete placement HIGH LOADS - 30,000 POUNDS/ STRAND Pretensioning Prior to concrete placement Generally performed at a “plant” HIGH LOADS - 30,000 POUNDS/ STRAND NEED SOMETHING TO JACK AGAINST Posttensioning After concrete placement (& curing) Generally performed at the jobsite JACK AGAINST THE POURED/CURED CONCRETE
- “ Level surface of concrete supported on the ground” Loading; Carries little or no structural stress except: Transmission of superimposed loads LIVE LOADS - TRAFIC, EQUIPMENT, STORAGE Thickness & Reinforcing determined by: Continuity & Capacity of the soil STRENGHT / BEARING CAPACITY CONTINUITY OF SOIL CAPACITY Loads imposed
- Materials Custom Built of Lumber & Plywood 2x & PLYWOOD BUILT FOR LOCATION/USE/PROJECT “ STICK” BUILT” Prefabricated steel, fiberglass PARTICULAR PROJECT/USE HIGH REUSE - SHEARWALLS Standardized prefabricated panels ASSEMBLE FOR USE / STANDARD SIZES COMBINATION GANG FROMS MAY INCORPORATE SEVERAL Choice Depends on : Number of uses, Irregularity of wall HIGH USE - STEEL/FIBERGLAS/MDO Wall finish & tie spacing, HIGH FINISH EXPOSED VS STRUCTURAL Availability & Cost
- Layout, Install one side, anchor, & brace ANCHOR AND PLUMB Coat w/ Form Release EASE OF STRIPPING Install Reinforcing (or after form ties)
- Install Form Ties “ Small diameter metal rods which hold the forms together (remain in the wall) MANY DIFFERENT TYPES HYDROSTATIC LOAD
- One-Way Slab System “ Spans across parallel lines of support furnished by walls and/or beams” Limited Span Length One-Way Joist System Span Greater Distances, “Less Dead Load” DEAD LOAD OF SLAB / “TENSILE” CONCRETE Spaced ribs or joists w/ a thin top slab 3-5” SLAB Utilizes “pans” (metal, plastic, fiberglass) HIGH NUMBER OF REUSES Wide-Module or “Skip-Joist” System
- Bay Spacing - Square or Irregular SQUARE - TWO WAY Span Length GREATER - JOIST VS FLAT SLAB Loading HIGHER LOADS - DEEPER SECTION Ceiling Treatment EXPOSED - FLAT SLAB Lateral Stability HIGH STABILITY - DEEPER SECTION
- Prior to Formwork Construction Prepare, submit, & approve Engineered Shop Drawings MAY TAKE WEEKS FORMWORK DESIGN FORMWORK SUPPORT RESHORE AMOUNT & PLACEMENT ALL HAVE SOME IMPACT ON REQUIRED AMOUNT OF FORMWORK ALSO AFFECTED BY CONCRETE DESIGN & SCHEDULE FRPS supporting walls/columns
- Set Beam Bottoms (if required) Erect Beam Sides Form Slab OPTIONS SCAFFOLD - SINGLE / GANGED TABLES LARGE COST - MINIMZE LABOR Install MPE sleeves, block outs, “Cast in” electrical roughin PENETRATIONS THROUGH SLAB OTHER OPTION - CORE Clean “Deck” & apply form release
- Place Reinforcing Generally START FROM THE BOTTOM UP Beam reinforcing Slab bottom & then top reinforcing
- Strip Formwork Re-shore May Extend 3-4 Floors Below Re-shore Purpose Support Construction Load Support the Weight of the next Floor
- Can be used with any framing system Reduce member size and/or Extend span capacity