Analisis Perbandingan Lendutan Jembatan Rangka Ruang Segitiga dan Rangka Ruang Segiempat

Abstract

The bridge is a structure that crossing the road with obstacles that exist under it without closing it out. The flow path can be designated for general traffic highway, rail, pedestrians, water flow or pipeline. While the types of barriers that exist underneath can be a river, ravine, highways, railways irrigation channels, valleys, seas and so on. Steel frame bridge is considered more advantageous when compared with other types of bridges. This is because the trunks of the steel frame received only axial compressive and tensile forces only. Keep in mind steel frame bridge more profitable than other types of bridge spans a distance of between 30-60 m. In general, steel frame bridge when viewed from the visible cross section will have a square shape. Some weaknesses of the square shape is less stable construction if there is no horizontal bracing if receiving load. In addition, heavy construction itself will be heavy because of the many wind bracing and ties to stabilize the construction. It made a large dead load will increase which will affect the deflection occurred. Deflection will be able minimalized manner, reducing the burden alone of the bridge. One way is minimalized deflection is replacing the square shape of the bridge to form a triangle (looks transverse). Technical specifications for the bridge space frame triangle and square space frame is the same quality of steel, the bridge span, bridge width, bridge height and weight are acceptable to both bridges are the same. To the load calculation rules use RSNI 02-2005 and design profiles using RSNI T 03, 2005. Before analyzing the deflection calculation of statics bridge first, conducted to know the style that happened on the bridge. Statics calculations on the bridge is calculated using auxiliary program SAP2000. After learning style that occurred in each bar triangular space frame bridge and quadrilateral space frame, each profile should be strengths of each bar, the stronger the stem - the stem that strung the smaller the deflection which occurs on the bridge. Based on calculations, deflection comparison triangular space frame bridge and quadrilateral space frame based on the effective capacity of the bridge bridge which has a triangular space frame rod pieces weighing as much as 141 kg experienced deflection 319246.1 15.6 cm when calculated using method 1 unit load and 15:35 cm obtained from the calculation SAP2000. While the square space frame bridge with stem 186 430212.2 kg experienced severe deflection of 12 cm, calculated using the unit load and use the tools available SAP2000 11.9 cm. Because the triangular space frame bridge having more than deflection permits deflection l/500 (BMS, 1992) or 12 cm for the bridge with a span of 60 m. So to find a triangular space frame bridge capacity load factor was changed to a triangular space frame bridge can meet the allowable deflection. After a load factor of the triangular space frame bridge replaced deflection 11:31 centimeters obtained, calculated using the program SAP2000 aids. Deflection for a square space frame bridge after the load factor was changed to meet permit deflections or less than 12 cm. As for the comparison of deflection based on the weight of the bridge gained weight triangular space frame bridge 425011.8 kg with a deflection that occurred 9.96 calculated using the method 1 and 10.4 units of load is calculated using auxiliary program SAP2000. Weight bridge triangular space frame obtained after the change the siz oef the profiles on the main girder, diagonal and below the main girder.