Steel Structure of a Tunnel Dormitory for the Armed Forces Troops

The current steel structure is used mainly as a dormitory for the armed forces troops, who are facing terrorist aggression. It is supposed that the structure of the dormitory can withstand 70 tons as a live load. Easy installation and dismantling for transportation are considered as essential requirements. The steel structure is processed of grade X42, with 8 mm thickness, according to the American Petroleum Institute specifications (API- 5L). The steel has a chemical composition comply with grade X42, as it contains (max.) 0.28 wt% C, 1.30 wt% Mn, 0.030 wt% P, and 0,030 wt% S. On the other hand, the steel sheets would possess mechanical properties as; 290 -496 MPa Yield stress, 414 -758 MPa Ultimate tensile strength, and 22% Elongation. The modulus of elasticity is considered as 20000 MPa. The main body of the dormitory steel structure consists of segments. Each segment consists of two halves of 200 cm diameter pipe with 8 mm wall thickness and 150 cm pipe length. The main body of the dormitory contains 2-3 segments. An additional subsidiary unit is usually constructed as a main entrance with vertical sides and arch roof. A Finite Element Analysis (FEA) was used through SAP 2000 software package as a tool for quick and precise physical simulation to apply the live and died loads and detecting any deflections, permanent deformations and moments about the X- and Y-directions in the steel structure of the tunnel dormitory. It is found that 8 mm wall thickness is the optimum, where the dormitory steel structure shows 2.72 mm maximum deflection under loading conditions, which represents 0.13 deformation% in the Z-direction. The moments are very low, as they reach to 0.023 and 0.066 t.m about the X- and Y-directions respectively.