Since the partial portion of pile cap and 5 piles of pier P5 of Hoping W. Rd overpass bridge were located within the region of HSR tunnel of TRUPO Panchiao extension project, therefore the underpinning method was adopted in order to solve this conflict. During the period of underpinning, the pier column and pile cap of pier P5 were demolished firstly then the new piles、pile cap and pier column were built. Because there was still not enough space to install the retaining wall for HSR tunnel excavation, the north side of new piles of pier P5 were required to provide as the piling retaining wall during HSR tunnel excavation. This paper presents the underpinning design and construction on pier P5 of Hoping W. Rd overpass bridge in order to offer as reference for case study.
The North Gate is a class 1 national historical monument which is located around the intersection of Chung-hwa Road and Chung-hsiao west Road. Taipei MRT Nankang line construction contract CN253B was planned to go underneath the vicinity of North Gate. For preservation purpose, the shield tunnel construction method was used. The near by also includes elevated highway ramps and some private-owned buildings. With a careful alignment study, a minimum tunnel radius standard was chosen to minimize the impact to the North Gate and other near by structures. However, the shield tunnels pass area underneath 70cm of the North Gate foundation can not be avoided.
Due to the importance of the North Gate, a building protection planning and evaluation study was conducted during the earlier detailed design stage. The JSG method of soil improvement was applied to isolate the negative impact from construction of shield tunnel method. During construction stage, the concept in design stage was implemented and settlement due to construction was controlled. This paper depicts the problems and solutions during construction. After the shield tunnels were completed, the cumulative maximum settlement of North Gate was less than 21mm and very small under the strict criteria. This is the first successful construction case which also took good care of historical monument.
This Paper describes the underpinning work of Han-Seng Road Overpass .The construction process involved a temporary supporting steel frames to support the bridge load and transfer the load to two exterior slurry walls. After demolish the pier and foundation pile, an underpinning slab was constructed. On top of the slab , a pier was rebuilt. To maintain the daily traffic and the safety of the Overpass during underpinning , an automatic monitoring system was installed to observe movements and tiltings. This paper also discuss the operation of the automatic monitoring system.
In regard to predict the relation of load-settlement of pile under axial load, there have not yet an analytical method both simple in calculation and easy for parameter selection. The main reason is that the mechanism of the interaction between pile and soil is very complex. The mechanism of the interaction is not only influenced by the factors of soil strength and stiffness, but also the construction method, degree of disturbance and the roughness of pile shaft.
The approximate analytical method for ideal elasto-plastic soil suggested by Su and Shu(1996) is suitable for piles penetrated into multilayered soil. Based on the record of two field tests, this presentation is plan to check the correctness of the suggested method. After comparing the results of computed and tested data, it was confirmed this suggested method is very appropriate to use before the ultimate load of pile is achieved.
For rock blasting, not only rock properties and blast design must be considered, but also explosives properties has to be understood in order to reach optimum blast result. This paper is to introduce various properties of explosives, domestic current explosives and applications, and future developing trend for reference of blasting engineers.
The occurences of ground vibration are mainly dependent on processes of both earthquake and blasting operation. In contrast to uncertainty of earthquake, ground vibration due to blasting can be reduced by means of blasting design. This paper not only provides the descriptions of generation of ground vibration but also proposes some techniques for reducing the magnitude of ground vibration.