SLAB ANALYSIS DESIGN FOR HIGH RISK BUILDINGS IN SEISMIC AREA
Indonesia is the country through which the Indian-Australian Plate and the Pacific Plate meet. Therefore, Indonesia is an earthquake prone country. On 24th December 2004, there was movement of the IndianAustralian Plate, resulting in an earthquake with 9,1 moment magnitude scale, with the distance from the epicenter to Medan as far as 400 km. Because of the earthquake, P.T. Indosat which is a seven stories building located in Medan, had cracks in its slabs, especially near the support area. The columns and beams of the building did not have any cracks. Almost entire floors had cracks, except the rooftop. The cracks varied between 0,7-12 mm in width. The 12 mm crack width occurred in the second floor. The slab structure are two way slabs with single reinforcement. The problem makes us to question the effect of the quake loads in slab design. Generally, a slab is design based only on gravity loads, and the design of a slab is similar to the design of a beam with single reinforcement. In fact, quake loads also need to be considered in slab design especially for high risk buildings. This paper presents how the earthquake loading will add to the moment result and the extent to which the result will influence the slab beam design in high risk buildings.