Starting at 4:47 p.m. on Saturday, February 15, 2014, Conco broke the Guinness World Record for the largest continuous mat pour in 18 ½ hours (1 ½ hours under the projected time). To verify the event, there was an official Guinness World Records adjudicator on-site. The mat pour was for the new Wilshire Grand Center that is being constructed in downtown Los Angeles, and is slated to become the tallest building in the U.S. west of the Mississippi.
*Photos by Gary Leonard
After some 5 months of excavation and shoring, Conco was finally ready to begin the preliminary mat foundation work. Starter footings and elevator pits had to be constructed before the nearly 7 million pounds of mat reinforcement was installed. Then came 18 miles of cooling pipes for thermal control. We were ready to go with a couple of days to dot the i’s and cross the t’s. We began the set ups for pumping which involved strategically placing 19 pieces of concrete placing equipment in and around the construction site. It was now time to place this nearly 20 foot thick mat foundation.
The massive mat pour required a fleet of 208 trucks that each made 10 to 14 concrete drops for a total of 2,100 trips over the 18 ½ hour period. All of the concrete was provided by eight concrete batch plants operating at full capacity and located within a 20-mile radius of the job site. The success of the pour depended upon everything going exactly as planned and with contingencies in place to reroute trucks around any traffic jams. Trucks had to arrive on time since concrete needs to be poured 90 minutes after it is mixed. Several streets in the area were closed off to traffic.
Prior to this record breaking event, the largest continuous mat pour had been for the Venetian Hotel in Las Vegas in 1999. During that event, 21,000 cubic yards of concrete were poured. For the Wilshire Grand, 21,200 cubic yards of concrete were poured with an official finish time of 11:30 a.m. Sunday morning. The skyscraper is expected to be completed in 2016 and opened to the public in 2017. The Wilshire Grand will be 1,100 ft. tall, to include a 900-room hotel, office and convention space as well as five levels of subterranean parking.