Hollowcore - Girder-Slab®

1 Hollowcore 101. Hollowcore is the most Common Practice: Camber versatile of all Oldcastle Whether you know it Precast concrete products or not, floors are the key element when it comes to S peed of construction for Hollowcore plank is unprecedented. No other flooring system can match the installa- hurricanes to high winds and seismic events. architectural freedom and design: their load bearing capacity has F ire safety. Concrete does not burn a direct influence on the need tion rate per day. for partition walls and other and can never be turned off or V ersatility. You can design plank to malfunction. Hollowcore plank has a structural elements of a building. work with steel, masonry, CIP, metal minimum hour fire rating. A struc- Hollowcore slabs are prestressed stud or precast building components. tural topping can increase that up to a floor elements with voids.

2 The 4-hour rating. excellent load-bearing capacity C lear spans. Column free interior space provides design freedom and lets you maximize the use of your space E fficiency. Run the numbers and estimate your next project in Old- and structural efficiency allows you to build large areas with fewer partition walls. Ultimately, this now and in the future. castle Precast Hollowcore plank. Sav- means greater freedom in design ings in cost and time will keep your D urability. Hollowcore plank is and architecture during and after project on time and under budget. construction as well as savings in resistant to nature from termites or material costs. See our web site for additional topics on Hollowcore plank: installation, toppings, openings, finished floors, specifying and more. Locations: Oldcastle Precast Building Systems 123 County Route 101.

3 Selkirk, NY 12158. 800-523-9144. Oldcastle Precast Building Systems 1401 Trimble Road Edgewood, MD 21040. 800-523-9144. C amber is inherent in all prestressed precast prod- ucts. It is the upward deflection created by the prestressed forces in the strands located below the center of gravity. This is required to resist design loads and in the Hollowcore plank it compresses the bot- tom more than the top. Span length, plank thickness and design load requirements will determine the amount of pre- stressing force needed in the plank, from which the engineer can calculate an estimated camber. The benefit of camber in prestressed precast concrete products is that it allows for longer spans, shallower depth sections and higher load car- rying capabilities than con- Get to know more about Hollowcore design and its ventional building materials.

4 Camber should not be specified as a design parameter. effects on camber. Differential Camber Theoretical Camber Minimize Differential camber refers to Theoretical camber is the calcu- The optimal storage time differential varying amounts of camber between adjacent Hollowcore lated upward deflection based on for plank in the yard is 2 to 3 camber by one planks. Camber differences oc- relevant design parameters. It is weeks. Extensive job schedule or more of these time dependent due to the curing delays and increased stor- cur because no two planks have of concrete and can vary signifi- age time can lead to camber methods: jack up the same exact strength gain, creep and exposure to the ele- cantly from actual camber on site. growth. This is especially true low pieces; shim ments in storage. Planks in the in the early summer where shorter planks warmer temperatures and low yard exposed to direct sunlight humidity accelerates the cur- at bearing; flash will experience more camber ing process.

5 Patch ; apply self- growth than plank in the shade. Adjacent planks with different leveling course. span lengths will differ in cam- ber as will those with different prestressing strand patterns. Important Considerations about Camber S pecify realistic design loads to avoid overly con- servative load requirements. M inimize differential plank camber prior to grouting keyways by one of more of the following methods: use temporary shoring to jack up low planks; use sandwich plates and bolts at mid span to draw planks vertically together; shim L imit plank span to depth ratio to 45. Increase plank thickness if necessary. shorter and low planks at bearing points; flash patch (feather) joints between adja- cent planks; apply self-leveling coatings (gypcrete) or use structural topping. I ncrease 2-inch topping overlays if maximum plank camber exceeds 3/4 inch.

6 Plan finished floor eleva- tions accordingly. A dvise subcontractors installing door frames to account for plank camber and topping if any. The information contained in this literature is for general information purposes only. The information is provided by Oldcastle Precast as a courtesy only. While we endeavor to keep the information up to date and cor- rect, we make no representations or warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability or availability with respect to the information, products, services, or related graphics contained in this literature for any purpose. Any reliance you place on such information is therefore strictly at your own risk. In no event will we be liable for any loss or damage including without limitation, indirect or consequential loss or damage, injury or illness, or any loss or damage whatsoever arising from loss of profits arising out of, or in connection with, the use of this literature.

7 Hollowcore 101. Engineer your Openings for a Common Practice: Openings Successful Plank Project Whether you know it or not, floors are the A wide variety of opening sizes and configurations can be accommo- dated using an Oldcastle Precast hol- T he general contractor and other trades are responsible for design coordination and field layout of all key element when it comes to architectural freedom and design: their load bearing capacity has lowcore floor system. They range from openings. Oldcastle will show open- a direct influence on the need large openings (>10-inches) to small ings larger than 10-inches square for partition walls and other core drills. on shop drawings if supplied early. structural elements of a building. Additional openings not shown on Hollowcore slabs are prestressed M ost common large openings include: HVAC, plumbing and electrical chases, hatch access at roof, returned approved shop drawings must have written approval from floor elements with voids.

8 The excellent load-bearing capacity Oldcastle's engineer. and structural efficiency allows trash chutes and skylights. you to build large areas with fewer S mall core drill openings include single plumbing risers, electrical G eneral contractors and other trades must field locate all openings prior to cutting them. partition walls. Ultimately, this means greater freedom in design lines, radiant heat tubing risers and roof and architecture during and after Oldcastle can cut large openings if drains. construction as well as savings in included in the scope of work. material costs. See our web site for additional topics on Hollowcore plank: camber, toppings, finished floor systems, specifying, installation and more. Locations: Oldcastle Precast Building Systems 123 County Route 101. Selkirk, NY 12158. 800-523-9144. Oldcastle Precast Building Systems 1401 Trimble Road Edgewood, MD 21040.

9 800-523-9144. T he best place to locate large openings is near the bearing point. This location has the least design impact to the floor system. Large openings near the bearing may require solid concrete areas that are done either in the plant prior to shipping or in the field after installation. Large openings near the mid-span of the plank will require more prestressing and will impact camber. S mall core drilled openings can be placed anywhere provided they are located in the hollow void of the plank and are small enough that they do not cut any prestress- ing strand. Any core drilled openings that cut through the Get to know more about strand must be accounted for in the design of the plank and carefully monitored in the field. Openings in Hollowcore Plank Any core drilled opening that cuts prestressing strand that was not accounted for in design Locating Openings Penetrations needs the immediate review of Openings are a critical compo- and locations as early as pos- Oldcastle's engineer.

10 For mul- nent to the design and layout of sible in the design process. It can affect fire tiple cores concentrated in one Hollowcore plank. It is extremely is also recommended that the rating; camber;. area, it is recommended that these are aligned and bunched important to give Oldcastle locations of penetrations are prestressing Precast all required opening sizes properly coordinated early together in order to reduce the enough so that the precast can strand; steel amount of coring perpendicu- be properly designed. However, headers; solid lar to the spans. it is possible that some open- cores; topping;. ings may need to be moved or thickness;. re-sized for structural reasons. Penetrations can affect the redistribution following design aspects: thick- of loading and Important Considerations for Openings ness; amount of prestressing; plank layout.