Case History Of Remediation Of Existing Building Inclination

In this thesis, based on the application of deep pushing and squeezing method in the remediation of a inclination of a warehouse in Tianjin Economic Develepment Area(TEDA), where is a typical soft ground, the various methods of remediation of building inclination is introduced and ground improvement methods involved in them.The No.2 warehouse of Tianjin No.833 department is located in TEDA. It is a one storey reinforced concrete bent frame structure with total 5575 m2 in area. The design of bearing capacity of ground within the building is 80kPa. It's required by design that the initially applied surcharge on the ground surface can not exceed 30 kPa , then the allowed maximum increasing of load each year is 10 kPa until the total pressure reach 80 kPa in the 5th year. The building is put into use after its construction has finished in June 2002, with more than 140 kPa surcharge was applied on to the ground surface. Due to that, subsidence of ground and settlement of columns within the building occurred, while heaved the ground north of the building. Moreover, the northern row of RC columns inclined with cracks in their south side near ground surface. The ground beam and the wall on it have vertical cracks. Until may, 2003, the ground subsidence observed was between 16 to 158 mm. The northern and eastern RC columns lean outward with the biggest movement of 186 mm gradient of 1.69 percent. This gradient exceeded the maximum allowed 0.3 percent specified by relative design code. Remediation and restoration is needed. Based on the analysis and simulation of the phenomenon, the subsidence and heave of ground, and the inclination of columns can be attributed to excessive surcharge applied. This caused the compression and horizontal movement of the underlying soft clay with 11.0 m to 14.5 m thickness, 3 m under ground surface. According to that, so the following remediation measures were adopted(1) To drill hole in the ground with warehouse to release excessive horizontal stress.(2) To install a contiguous bored pile outside the warehouse near the row of inclined columns, then a row of contiguous rammed reinforced concrete piles were constructed between piles under the row of inclined columns and the bored piles. This is aimed to push these piles which were curved 6~10 m under ground surface back to their normal position and thus to keep them vertical and straight.