Grand Casino Parking Structure
Biloxi, Mississippi

Location: N 30.39233° W -88.86809°

The Grand Casino parking structure in Biloxi, MS is an oceanfront, four-level garage constructed of precast concrete columns, spandrel beams, and pre-tensioned double-tee deck with cast-in-place reinforced concrete topping. The 2nd-level deck collapsed, apparently after being briefly lifted by storm surge. One hypothesis is that the deck immediately failed at midspan in negative-bending flexure when the positive moment at midspan induced by self weight was negated by the uplift pressure of the storm surge. When the downward load due to self weight was negated or reduced by the distributed upward load due to the storm surge, the internal moment from the prestressing caused the concrete in the flange at midspan to rupture in tension. (The flange is very lightly reinforced with wire mesh.) An alternative hypothesis is that the storm surge uplifted the deck and translated the double tees far enough to become unseated from girder corbels, causing the deck to drop to the ground floor.

Figure 1 shows the parking structure from the northeast corner; Figure 2 shows a view south along the east bay, including the 2nd floor spandrel beam of the north façade’s east bay and the double-tee, fractured at midspan, that had been on adjacent to it. Just visible behind the double tee is the roof of a relatively intact Mazda Miata that had been parked on the 2 nd floor. The spandrel beams had been connected to the columns at each end by two 3x3 clip angles, as shown in Figure 3. Similar very modest positive connection existed between the ends of the double tees and the girders supporting them. Figure 4 shows the corbels at the second and third floors at the northeast corner. Some architectural finishes covered the corners of the garage; these are visible in the figures as well. The garage measures approximately 150 ft (46m) by 300 ft (91m), with a roof deck 36 ft (11m) above grade.

The Grand Casino is located at 312 US 90, Biloxi MS; 30.39233° north latitude x 88.86809° west longitude, perhaps six ft (2 m) above sea level. Its exposure category according to ASCE 7-02 is C.