Construction is often thought of as a gradual process – one that takes significant time and planning to get right. However, not all projects are created equal. While a large office building may allow for a longer timeline, an emergency situation such as a collapsed bridge requires a more rapid solution.
This is where precast concrete comes into play. At G3 Quality, we’ve seen how precast concrete can cut down project times by up to 50% simply by doing the work in segments, and often help project owners with inspection and precast materials design.
Read on to learn more about precast concrete, why it’s so useful in emergency situations, and the role of ultra-high-performance concrete.
Traditional Construction vs. Precast Concrete Construction
As opposed to traditional building methods which carry out construction on-site, precast concrete is made off-site in separate components before the pieces are conjoined. Precast concrete also commonly contains ultra-high-performance concrete that binds pieces together, making for a far stronger material and a streamlined process that’s beneficial in emergency situations.
In California, there are two main methods of construction for large projects like highways and bridges. The first is to build everything from scratch, completely on-site. It’s a speed-oriented process that’s typically used for emergency situations, such as urgently replacing a bridge that’s lost its structural integrity.
An example is if a truck catches fire while underneath a bridge, damaging the integrity of the concrete. Under these circumstances, engineers would need to demolish and rebuild that section rapidly.
The second method is a bit more complex but still used by agencies such as Caltrans for emergency situations. By using precast concrete that’s bolstered by ultra-high performance concrete (UHPC), engineers can significantly boost the PSI of materials in a swift fashion.
Precast Concrete Construction
As opposed to the first method which builds everything on-site, precast concrete components are fabricated off-site at a precast yard. Once built, the pieces are transported and assembled like a kit of parts at the job site.
Using precast members streamlines construction by moving much of the work to a controlled plant environment. UHPC is far stronger than conventional concrete, with a compressive strength reaching 20,000 psi versus 2,000 to 6,000 psi for regular concrete materials in connecting the precast members together to make a solid unit.
For this reason, whole projects can be carried out using precast concrete. UHPC is mainly used as a binder that ties precast structures together and has been employed in countless major projects on the West Coast. The Paramount Bridge in Southern California is one example of an emergency replacement project that was completed in a manner of a few months versus 6 months to a year.
“By precasting concrete members with UHPC, not only can you achieve superior concrete strength, but you can do so in a rapid fashion. It’s the answer for urgent bridge reconstruction projects, especially considering the ductility of UHPC, which allows it to handle slight bridge movements without damage or breakage.”
- Marc Robert, Technical Services Director, G3 Quality
Precast Concrete for Emergency Situations
UHPC cement is highly specialized, containing a combination of reactive powders, limestone, quartz, flour, fine sand, and organic fibers that increase its ductility and strength. It can be cast between precast members to bond them together, resulting in a significantly higher strength than individual components. This bonded strength can reach up to 20,000 psi – far exceeding that of normal concrete.
Precast members with UHPC are often turned to in the event of an emergency, most often bridge reconstruction, since precast pieces can be rapidly manufactured and trucked in for faster rebuilding.
In fact, by piecing together precast members in segments, many projects can be done in half the time it takes with traditional on-site methods. The material is also extremely ductile and can better handle bridge movement without breaking, making it a preference with such projects.
Thanks to its superior strength and dependability in emergency situations, precast concrete with UHPC has become the material of choice for urgent bridge reconstruction, and large-scale projects, and its resilience against natural disasters and heavy environmental conditions.
G3’s Precast Concrete Expertise
Precast concrete is highly popular for its strength and speed, but without the right checks and balances, your UHPC may be lacking quality. To ensure your materials are up to par, you need a QA/QC partner with both industry credibility and deep knowledge of precast and UHPC concrete. Enter G3 Quality – SoCal’s preferred geotechnical engineering firm.
The team at G3 Quality is deeply familiar with precast concrete and UHPC and has helped countless project owners qualify their precast materials for project and agency requirements. Thanks to our state-of-the-art materials testing labs located throughout California, we can also help you identify the perfect mix for your precast materials, guiding you at every stage of the process. Fill out a form on our Contact page to keep your materials in line with project and safety