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Numerical Modelling & Design of Unreinforced Construction Joint for Reinforced Concrete Substructures with Concrete Shrinkage & Creep

Raymond W. M. Lo and Yunita Dian Pratiwi
Aurecon NZ Ltd, Auckland, New Zealand

Abstract—Nowadays rapid urban growth always requires intensive development of underground infrastructure net-works. New reinforced concrete substructures may need to be built adjacent to existing ones sharing a common dia-phragm wall with unreinforced construction joints at the roof and the base slabs. These unreinforced construction joints need to provide adequate support for the adjacent existing substructure during construction stage and for long term when the time dependent creep shrinkage movement of the substructure becomes significant. This paper presents design details and a soil structure interaction finite element computer model for the unreinforced construction joints. These are applied to the impact assessment for the Perth City Busport substructure construction adjacent to the existing Perth-Fremantle Rail Tunnel. The effects on the existing rail tunnel structure due to the short term and long term shrinkage and creep movements of the Busport are found to increase the lateral displacement, bending moment and shear by up to 30%. However, the shrinkage and creep effect steadies at about 500 days after casting.
 
Index Terms—unreinforced construction joint, shrinkage, creep, substructure, numerical modelling

Cite: Raymond W. M. Lo and Yunita Dian Pratiwi, "Numerical Modelling & Design of Unreinforced Construction Joint for Reinforced Concrete Substructures with Concrete Shrinkage & Creep," International Journal of Structural and Civil Engineering Research, Vol. 4, No. 3, pp. 248-253, August 2015. doi: 10.18178/ijscer.4.3.248-253