Laying it on Thick at Morgan State
One of the most impressive features of Morgan State University’s new Center for Built Environment and Infrastructure Studies (CBEIS) is the new seismic simulator. Designed by Hord Coplan Macht in association with The Freelon Group, the CBEIS houses one of only a few bi-axial simulators of its kind on the east coast. This structure is a part of the overall CBEIS building; however, it is isolated with insulation and air gaps so that the seismic research does not affect the remainder of the building. This simulator is capable of shaking 23,000 pounds of test specimens and producing seismic activity up to 9.0 on the Richter scale. Additionally, the test facility houses a strong wall for torsional testing of materials.
To accommodate the tremendous loads that this bi-axial simulation table and its associated actuators would place on the structure of the building, an enormous concrete mass slab had to be poured. This slab is fourteen feet thick with numerous interstitial space block-outs to provide the necessary support for these massive loads and the necessary pathways for hydraulic lines to feed the actuators.
The structure required several challenging construction techniques. Due to the depth of the slab, the specifications required three separate pours, each four to five feet deep. Each pour took more than 14 hours to place and finish in the intricate lattice of reinforcing steel. Schuster Concrete, Inc. was the concrete contractor for the majority of the seismic simulator portion of the CBEIS.
In addition to the challenge of the 14-feet thick slab, there was the added challenge of a low level of tolerance for the rebar and anchor bolt placement. The bolts had to be within 0.0625” to accommodate the actuators for the simulator table. The strong floor has a tolerance of 20/1000 of an inch to accommodate the precision of the tests to be implemented in the facility.
This critical component of the construction required numerous checks and double checks of the layout prior to placement of the concrete. High level surveys were conducted for verification of bolt locations upon curing of the concrete.
With completion of the CBEIS, Morgan State University is a one of a handful of facilities in the United States studying the effects of seismic activity on various structures and materials in the quest to build structures that can withstand earthquakes and save lives.