Consistent Formwork Pays Off
The cost of formwork on a reinforced concrete construction project can be significant — usually 50 percent or more of the total cost of the structural frame!
As designers and engineers, it's important to understand how reinforced concrete buildings are constructed. Consulting a formwork contractor in the early stages of the project to provide input can result in significant cost savings.
Uniformity and consistency are key. Select one framing scheme and use it throughout the project as often as possible. Space the columns uniformly and make all the columns the same size as often as practical over the height of the building. Keep all of the beams and joists the same depth.
By doing this, the formwork contractor needs only a few sets of forms that can be used over and over again. This will also enable the construction crew to get into a certain "rhythm" of erecting and stripping the forms, which will decrease overall construction time and reduce costs.
Steps for Formwork and Structure Economy
- Study the architectural drawings.
- Working with the design and construction teams, establish column locations as uniformly as possible keeping orientation and sizes constant wherever possible.
- Use CRSI Concept to investigate the viability of various framing systems and to obtain preliminary member sizes and cost estimates for each system.
- Select a structural framing scheme based on the best balance between cost of structure and architectural programming requirements.
- Distribute preliminary structural drawings of selected framing scheme to all design and construction team members for their input.
- Plan your structure prior to design and detailing. Work with the formwork contractor to minimize costs. Keep the structure as simple as possible and use standardized member sizes to allow maximum reuse of forms.
- Be sure to include comprehensive details of all of the typical and non-typical structural members. This helps the reinforcement detailer and will most likely minimize the RFIs prior to and during construction.
- Include in your project specifications such items as minimum stripping time for formwork and a high, early strength concrete mix. These will help minimize construction time and related costs.