To browse Academia. Log in with Facebook Log in with Google. Remember me on this computer. Enter the email address you signed up with and we'll email you a reset link. Need an account? Click here to sign up. Download Free PDF. Chong Yong Ong. A short summary of this paper. Applied Mechanics and Materials Vol.
Precast concrete sheetpile designed to restore and protect a road embankment, undergoing continuous settlement in soft ground condition in Jerlun and Kuala Sanglang in the state of Kedah, Malaysia is presented. The road built on soft ground has been in service for several years with some anticipated settlements.
Major defects in the form of uneven settlements were spotted after few years of service. A survey was conducted and 5 spots along a 30m to 40m long stretch experiencing about mm settlements relative to the centerline of the road.
Several attempts have been made to backfill and re-surface the affected areas but the road conditions did not last, posing danger to motorists. Investigations have revealed slip circles did occur at the affected areas with signs of lateral movements of earths towards the river.
Precast concrete sheetpiles were designed to stabilize the road embankment to prevent further lateral movements of earth due to vehicular loads on the road. Analysis and design of the sheetpile system are presented. Construction aspects related to handling, installing and finishing works at site are highlighted. Introduction Today, due to the increasing number of vehicles used on roads, more roads are being constructed to cater for the massive traffic volume.
They are now built across rivers, hills and mountains in order to link countries, cities or districts. For the roads built adjacent to river on soft ground, there is always problem caused by the road users. The major problem is the settlement of road embankment near to river. Figures 1. However, such measures are found to be not effective in the long run.
In order to solve this problem, a new Precast Concrete Sheetpile System was developed. Precast Concrete Sheetpile System The development of reinforced concrete since late of 18th century by Francois Hennebique has brought the innovation to current concrete structures [1]. One of the current trend is to prefabricate components which is cost effective and short in construction period. Taking full advantage of the great features of precasting techniques, use of precast concrete sheetpile has been attempted as a solution to road embankment.
The basis of the above idea is that precast concrete flexible retaining wall in sheet pile form as shown in Fig. The lateral earth pressure from road embankment and river bed has significant effect on the requirement of strength and stiffness of the precast concrete sheetpile.
Therefore, adequate designed length of sheetpile is necessary in order to make the whole system functioning effectively. Figures 2. Precast Concrete Sheetpile System as road embankment protection Description of Projects The above road embankment protection using precast concrete sheetpile has been implemented in two projects. Project 1 Jerlun, Kedah : The project site is located adjacent to the Korok River in the state of Kedah, Malaysia which supplies water to canal at northern part of Kedah paddy region.
The road embankment is the only main road to the nearby town of Jitra. Below are some site constraints when carrying out the work: a Limited space for stacking stock of precast concrete sheetpile b The main road cannot be blocked during construction period b Minimum disturbance and vibration by construction works due to village area nearby A total length on plan of 30 meters precast concrete sheetpile was built.
The road embankment along the canal was finally decided to be blocked due to insufficiency of road width for traffic during construction. However, alternative road for the road users was provided. There are several site constraints when carrying out the work: a Limited space for stacking stock of precast concrete sheetpile b Minimum disturbance and vibration by construction works due to existence of electrical cables and village area nearby The total length on plan of precast concrete sheetpile constructed was 40 meters.
The maximum exposed height is 3 meters. Precast sheetpile alignment was decided to be 2 meters from the road side.
Elevation section for these two projects is shown in Fig. Schematic diagram of precast concrete sheetpile is shown in Fig. Precast concrete sheetpile: a Typical section, b Elevation section Figures 4.
Schematic diagram of precast concrete sheetpile Design and Development As mentioned earlier, proper design to ensure sufficiency of strength and stiffness of the precast concrete sheetpile has been carried out. Precast concrete floor slabs are lifted from the ground up to the final height by lifting cranes.
The slab panels are lifted to the top of the column and then moved downwards to the final position. Temporary supports are used to keep the slabs in the position until the connection with the columns has been achieved. The precast concrete column elements are 1 to 3 stories high. The reinforced concrete floor slabs fit the clear span between columns. After erecting the slabs and columns of a story, the columns and floor slabs are prestressed by means of prestressing tendons that pass through ducts in the columns at the floor level and along the gaps left between adjacent slabs.
After prestressing, the gaps between the slabs are filled with in situ concrete and the tendons then become bonded with the spans. Seismic loads are resisted mainly by the shear walls precast or cast-in-place positioned between the columns at appropriate locations. The stresses developed in precast elements during the period from casting to final connection may be more critical than the service load stresses.
Special attention should be given to the methods of stripping, storing, transporting, and erecting precast elements. When precast members are incorporated into a structural system, the forces and deformations occurring in and adjacent to connections in adjoining members and in the entire structure should be considered.
The structural behavior of precast elements may differ substantially from that of similar members that are monolithically cast in place. Design of connections to transmit forces due to shrinkage, creep, temperature change, elastic deformation, wind forces, and earthquake forces require special attention. Details of such connections are especially important to insure adequate performance of precast structures. Precast members and connections should be designed to meet tolerance requirements.
The behavior of precast members and connections is sensitive to tolerances. Design should provide for the effects of adverse ccombinations of fabrication and erection tolerances. Tolerance requirements should be listed on contract documents, and may be specified by reference to accepted standards. Tolerances that deviate from accepted standards should be so indicated.
Whether this information is to be shown on the contract documents or shop drawings depends on the provisions of the contract documents. The shop drawings should show, as a minimum, all details of the precast concrete members and embedded items. The contract documents may specify that portions of connections exterior to the member are also to be shown on the shop drawings.
The contract documents should show the loads to be considered in design of the precast concrete elements of the structure, and they should indicate any special requirements or functions for example: seismic loads, allowance for movements, etc.
In this case, the shop drawings should include complete details of the connections involved. Precast concrete structure consisting of solid wall panels and hollow core slabs. It is noticed that large panel construction performs better than frame system.
However, in areas of high seismic risk, structures must be designed to respond safely to the dynamic forces imparted into the structure. Innovations in joint design are improving the connection systems in precast concrete structures and making them increasingly suitable for use in such areas.
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