Accelerated precast construction (APC) is much like accelerated bridge construction, where precasters can perform time-consuming formwork assembly, concrete pouring and curing offsite in the controlled environment of an automated or fully robotic precast plant. The advantages of APC include project delivery time, product quality, durability, safety and economics. In addition, precast concrete pipe and boxes can be reused and repurposed.
Hurricane Ingrid and Tropical Storm Manuel caused the collapse of a vehicular bridge in Coyuca de Benítez, Mexico, in September 2013. Standard-sized 96-in.-diameter reinforced concrete pipe (RCP) produced by American Concrete Pipe Assn. member Tubocreto was used by the Ministry of Communications and Transportation (SCT) to temporarily replace the collapsed bridge. The SCT’s decision to work with its local concrete pipe supplier to resolve a situation that threatened the health and safety of nearby communities—as well as the economy of a region (including the tourist industry in Acapulco)—heralds a new era in which standard-sized concrete pipe can be included in rapid response strategies (such as APC) to address natural and manmade calamities.
The bridge at Coyuca de Benítez was 110 m long. A temporary structure to ford the shallow crossing required 112 units of 96-in.-diameter RCP with lay lengths of 2.4 m. The design required 28 culverts with four units of pipe comprising each structure. The 28 structures were drawn together and stabilized using ¾-in. steel cable. After the decision to build the temporary bridge was made, 300 workers using excavators, compactors, loaders and dump trucks completed the structure in ten days and reopened the region to commerce and the traveling public.
In the case of the Coyuca de Benítez bridge collapse, APC minimized the impact on the aquatic environment through rapid construction. The concrete pipe will be removed after the bridge is rebuilt and then reused for other purposes. The temporary culvert structure is a very good example of rapid-response strategies being developed throughout North America for failed infrastructure caused by major storms.
American policymakers, industries and academics are working rapidly to introduce ways to increase disaster resilience. For example, in 2011, Hurricane Irene damaged more than 2000 culverts in Vermont. Since Irene, the Vermont Agency of Transportation and many municipal public works agencies have been given the ways and means to specify concrete for the replacement or construction of culverts. Concrete culverts can be specified under the Moving Ahead for Progress in the 21st Century Act, allowing states to specify the appropriate pipe material without appearing biased. Combined with new ways to specify pipe and culvert materials, APC is a novel way to build and rebuild small bridges, culverts and temporary detours.
