PLANNING TO REPAIR THE APPROACH SLABS BRIDGE MUARA TABIRAI, RANTAU – KANDANGAN

Muara Tabirai Bridge is on the border between Rantau and Kandangan District ,which is precisely is on the street of Kalumpang-Margasari, the village of Paci, Kalumpang subdistrict. Increasing economic growth has led to the economy of the population being affected by the development of the city, gradually increasing in economic sectors as a result of global economic growth. The increase in this economy is due to the growing industry in the area. This is accompanied by the increase and needs of the population in the area that resides in the region. Unfortunately, after one year of construction of Muara Tabirai Bridge, the approach slabs bridge in the direction Kandangan on the right side suffered a decrease in the soil to damage the asphalt, due to the possibility of a landslide on the side of the road, then the implementers make alternative repairs by using a bronjong which makes the load heavier than before so that the ground that supports the burden of the heap, bronjong and traffic load can not withstand and So in this final task is done repair on the ground soil and design a retaining wall that is more suitable for the condition of the landThe basic soil repair method used is by a phased heap (Preloading) combined with the Prefabricated Vertical Drain (PVD) ,which serves as a water and air release on the soil, thus experiencing a consolidated degree of 90%. And for retaining wall against the side of the heap is used sheet pile with the type of free-standing ,which is suitable for the location of the pile located in the river. After that, the calculation of budget plan (RAB) on the Land, improvement Project,From the result of calculation obtained, a gradual heap (Preloading) carried out 0.2 m/week ,and ,a high critical heap (HCR) obtained on the high end of the plan (HR) 3.14 m obtained a security figure (SF) of 1.148 so that the heap used the soil reinforcement that is Mini pile erection so that the safety number (SF) reaches more than equal to 1.5 Prefabricated Vertical Drain (PVD) is used specification of the product PT. Teknindo Superior System installed when before done the filling is on the ground ground, planning Prefabricated Vertical Drain (PVD) using a triangular mounting pattern with a distance between PVD 1.25 m, depth 28 m and the time required is 21 weeks. Planning of soil retaining structure used is cantilever sheet pile type, obtained a total length of sheet pile of 20.938 m at STA 0 + 275 on the left and right side of the bridge. The budget plan for this basic land improvement project is Rp. 30,886,527,167

Improvement of a bridge connection node with embankment by applying curved approach slabs

The article is devoted to improving the bridge connection node with embankment by application of curved approach slabs. The most important request by arranging of bridge connection with embankment is to ensure soft entry of transport from the approach embankment to the bridge for the entire period of operation. However, overtime on the road sections of bridge connection with embankment appear soil collapsing, cracks and birdbaths in the carpet. This problem is partially solved by the installation of reinforced-concrete approach slabs buried in the connection zone between the abutment and the approach embankment. Despite the use of straight approach slabs in the bridge-connection node with embankment, the formation of bumps of grade profile is observed, they reduce road safety, worsen the technical condition of vehicles, cause discomfort to the driver and passengers. From the structural and technological point of view, request by arranging of bridge connection by curved approach slabs higher functional quality can be achieved. Due to the soft passage of bridge connection node, it is possible to reduce the negative shock-dynamic effects, which will increase the durability of the connection node and approach road pavement. The article presents several possible to use bridge connection node structures through the use of curved approach slabs: concave, convex and S-shaped. A comparative analysis of bridge-connection structural versions will reveal the most effective construct that can ensure soft passage of the bridge connection node with approach embankment.

Dynamic effects of vehicles on the elements of bridge structures due to deformation of the approach slabs

As part of the study, a field experiment was conducted, the results of which were used to evaluate the dynamic effects of vehicles on the elements of bridge structures due to deformations of the approach slabs. Drawdowns of the pavement at the interfaces of artificial structures with approaching embankments lead to the development of additional dynamic transport impacts, which give them accelerations reaching 1.8 m/s2 (for the studied objects). Taking into account a detailed survey of the places of interfacing bridges with approaching embankments, there has been proposed a method for eliminating the causes and consequences of the deflection of approaching slabs without disassembling existing structures. The method is based on the injection way of filling voids and fixing soils. A method of eliminating the causes and effects of deflection of approaching slabs without disassembling existing structures, based on the injection method of filling voids and fixing soils, ensuring evenness on the site by milling the coating with the laying of the leveling layer.

Parametrical Study of the Shear Resistance of the Approach Slabs

The transition zone of the road bridges is located right behind the abutment. Function of this structure is to ease the vehicle transition from the bridge on the rigid support to the embankment with much smaller stiffness. The main function of the approach slab is, as a part of the transition zone, helping the backfill to overcome different stiffness of the bridge foundations and embankment. The paper deals with shear resistance of the slabs for different lengths and widths. Parametrical study was performed according to Eurocode loading model 1 (Uniformed distributed load and Tandem system). Each of the analysed slabs was loaded with sets of different TS positions and location of the loading lanes. Envelopes of the shear forces of the approach slabs were analysed for each type of the slab. After that shear resistance of the slab with or without the shear reinforcement was calculated. The slab was divided into areas with same shear reinforcement distribution. The analysis is the part of the engineering tool for the bridge designers. According to length and width of the slab, the engineer can easily choose the shear reinforcement diameter and its distribution. The tool also provides the construction details of the shear reinforcement. There will be also the option for the reinforcement design of the slab, with hints for the structural scheme and calculation method.

Investigation on the performance of bridge approach slab

In Egypt, where highway bridges are to be constructed on soft cohesive soils, the bridge abutments are usually founded on rigid piles, whereas the earth embankments for the bridge approaches are directly founded on the natural soft ground. Consequently, excessive differential settlement frequently occurs between the bridge deck and the bridge approaches resulting in a “bump” at both ends of the bridge deck. Such a bump not only creates a rough and uncomfortable ride but also represents a hazardous condition to traffic. One effective technique to cope with the bump problem is to use a reinforced concrete approach slab to provide a smooth grade transition between the bridge deck and the approach pavement. Investigating the geotechnical and structural performance of approach slabs and revealing the fundamental affecting factors have become mandatory. In this paper, a 2-D finite element model is employed to investigate the performance of approach slabs. Moreover, an extensive parametric study is carried out to appraise the relatively optimum geometries of approach slab, i.e. slab length, thickness, embedded depth and slope, that can yield permissible bumps. Different geo-mechanical conditions of the cohesive foundation soil and the fill material of the bridge embankment are examined.