Effects Of Construction Sequence Research Articles

Simulating mechanical response of GRS walls with different construction methods

GRS walls are constructed using a variety of fascia such as modular blocks, full height panels, Gabions, etc., which involves different construction sequences. The simulation of construction sequence is important in numerical modeling for understanding the evolution of deformation profiles and reinforcement forces with different fascia and corresponding construction methods. In this study, detailed Finite Element modeling of the GRS wall using OpenSEES as a numerical tool is presented. It includes discussion on the steps involved in simulating construction methods of wall with block and full height panel fascia along with their impact on overall response. A simple staged construction technique is adopted in simulation. The issues and techniques involved in the simulation of staged construction sequence and compaction stresses are explained. The considerable effects of construction sequence and modeling simplifications on deformation profile and reinforcement force distribution are discussed in detail.

Effects of construction sequence and pace on the stability of high embankments founded on soft marine clay

The construction of high embankments in regions where the soils are predominantly soft and consist of marine clay deposits with low shear strength poses special challenges. Due to the high water content of marine clay deposits, an increase in applied stresses results in excess pore water pressures and a consequent reduction in shear strength. The sequence, pace, and duration of embankment construction play an important role in determining the stability of high embankments built on these soft soils. In this paper, the effects of these parameters on embankment performance are examined by utilizing a case study of an embankment failure which occurred in 2006 during the construction of a four-lane highway leading to the Canada-USA border crossing in St Stephen, New Brunswick, Canada. The St. Stephen highway embankment, with a design height of 14 m, failed at a height of approximately 12.3 m. The problem under consideration is modelled by using finite element analyses with the PLAXIS 2D software. Modelling is carried out with a staged construction technique, where the pace of embankment construction depends on the thickness of the fill layer added at each construction stage, and the time allowed for consolidation following the addition of each layer. Fill layer thicknesses ranging from 0.6 m to 7 m are used, in combination with consolidation times ranging from 1 to 64 days. The results obtained show that the stability of embankments founded on soft soil deposits increases as the pace of construction decreases and as the time allowed for consolidation increases.

Simulation of subway tunnel construction process based on fi-nite element analysis

Simulation of subway tunnel construction process based on fi-nite element analysis

Application of constitutive model in simulation analysis of tunnel construction

Application of constitutive model in simulation analysis of tunnel construction

Effects of Construction Sequences and Volume Loss on Perpendicularly Crossing Tunnels

The number of constructed tunnels has been gradually increasing for the past decades due to rapid development in urban areas. However, the soil‐structure interaction problems arising from perpendicularly crossing tunnels attract relatively little research attention in the past. In this study, six three‐dimensional finite element analyses were conducted to simulate tunnel excavation nearby a perpendicularly crossing existing tunnel, in an attempt to investigate the effects of construction sequences on cross‐cutting tunnels. The hypoplastic constitutive model for sand is adopted in the numerical analysis to consider the soil small‐strain stiffness. Computed results are presented and discussed in terms of ground surface settlement, displacement and deformation of the existing tunnel, and bending moment induced on the existing tunnel. The stress‐transfer mechanism in soil nearby the existing tunnel due to tunnelling is also studied.

Effect of construction sequence on three-arch tunnel behavior-Numerical investigation

This paper concerns a numerical investigation on the effect of construction sequence on three-arch (3-Arch) tunnel behavior. A three-arch tunnel section adopted in a railway tunnel construction site was considered in this study. A calibrated 3D finite element model was used to conduct a parametric study on a variety of construction scenarios. The results of analyses were examined in terms of tunnel and ground surface settlements, shotcrete lining stresses, loads and stresses developed in center column in relation to the tunnel construction sequence. In particular, the effect of the side tunnel construction sequence on the structural performance of the center structure was fully examined. The results indicated that the load, thus stress, in the center structure can be smaller when excavating two side tunnels from opposite direction than excavating in the same direction. Also revealed was that no face lagging distance between the two side tunnels impose less ground load to the center structure. Fundamental governing mechanism of three-arch tunnel behavior is also discussed based on the results.

Simulations of short- and long-term deflections of flat plates considering effects of construction sequences

The structural designs of RC flat plates that have no flexural stiffness by boundary beams may be governed not by strength conditions but by serviceabilities. Specially, since over-loading and tensile cracking in early-aged slabs significantly increase the short- and long-term deflections of a flat plate system, a construction sequence and its impact on the slab deflections may be decisive factors in designs of flat plate systems. In this study, the procedure of simulating slab deflections with considering construction sequences, concrete cracking, and long-term effects is proposed. The proposed method is practically useful, as it can predict well the slab deflections at construction and service stages only with a few input data. The proposed method is verified by comparisons with measured results in a real-scale test.

Simplified sequential construction analysis of buildings with the new proposed method

Correction Factor Method (CFM) is one of the earliest methods for simulating the actual behavior of structure according to construction sequences and practical implementation steps of the construction process which corrects the results of the conventional analysis just by the application of correction factors. The most important advantages of CFM are the simplicity and time-efficiency of the computations in estimating the final modified forces of the beams. However, considerable inaccuracy in evaluating the internal forces of the other structural members obtained by the moment equilibrium equation in the connection joints is the biggest disadvantage of the method. This paper proposes a novel method to eliminate the aforementioned defect of CFM by using the column shortening correction factors of the CFM to modify the axial stiffness of columns. In this method, the effects of construction sequences are considered by performing a single step analysis which is more time-efficient when compared to the staged analysis especially in tall buildings with higher number of elements. In order to validate the proposed method, three structures with different properties are chosen and their behaviors are investigated by application of all four methods of: conventional one-step analysis, sequential construction analysis (SCA), CFM, and currently proposed method.

시공단계별 영향을 고려한 터널 전력구의 유한요소해석

In this paper structural analysis of underground electrical power cable structures which is excavated below the surface of the earth in the downtown area is carried out considering the effect of construction sequence. There are many various life-line facilities below the surface of the earth in the downtown area. MPDAP was used for finite element analysis of underground electrical power cable structures. Three typical sections are simulated by finite element models. Unbalanced equilibrium problems may be occurred when conventional finite element procedures were used for simulation of tunnel excavation. Therefore equilibrium perturbation concept was applied to solve these problems. The effects of time-dependent deformations in advancing tunnel excavation are considered in the stages of construction sequences as using the load distribution factor. It is shown that values of maximum displacement of both soil and rock surrounding underground electrical power cable structures obtained by our numerical studies are less than allowable values.

Effect of Construction Sequence and Soil Nonlinearity On The Behavior of Sheet Pile Walls

Effect of Construction Sequence and Soil Nonlinearity On The Behavior of Sheet Pile Walls

Effects of Axial Shortening of Columns on Design and Construction of Tall Reinforced Concrete Buildings

Axial shortening of columns due to long term creep and shrinkage is inevitable in tall reinforced concrete buildings. However, calculation of exact values of axial shortening is not a straight forward task since it depends on a number of parameters such as the type of concrete, reinforcement ratio, and the rate and sequence of construction. All these parameters may or may not be available to the design engineer at the preliminary design stage of construction. Furthermore, long term shortening of columns could affect the horizontal structural members such as beams and floors and hence could affect the finishes and partitions. Therefore, a reasonable idea about the probable axial shortening could be important for construction engineers and project managers as well. In this study, the effects of construction sequence, rate of construction, and grade of concrete on axial shortening are determined based on a number of case studies covering 10–40 story range. These are presented as a set of guidelines so that the effect could be taken into account approximately, especially at the preliminary design stage and also during the construction phase.