scholarly journals The Effects of Multipropped Deep Excavation-Induced Ground Movements on Adjacent High-Rise Building Founded on Piled Raft in Sand

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Mukhtiar Ali Soomro ◽  
Naeem Mangi ◽  
Wen-Chieh Cheng ◽  
Dildar Ali Mangnejo
Keyword(s):  
Three Dimensional ◽  
Bending Moment ◽  
Small Strain ◽  
High Rise ◽  
Piled Raft ◽  
Interstorey Drift ◽  
Numerical Parametric Study ◽  
Soil Behaviour ◽  
Pile Length ◽  
Storey Building

In this paper, a three-dimensional numerical parametric study was conducted to predict the deformation mechanism of a 20-storey building sitting on a (4 × 4) piled raft to an adjacent 25 m deep basement excavation. The influences of different excavation depths were investigated. An advanced hypoplastic sand model (which is capable of taking small-strain stiffness into account) was adopted to capture soil behaviour. The computed results revealed that excavation adjacent to a building resting on the piled raft caused significant settlement, differential settlement, lateral deflection, and interstorey drift in the building. With settlement due to working load (i.e., 4.8dp%), the total settlements of the building (7.8dp%) exceed the maximum allowable foundation settlement (i.e., 50 mm). In addition, substantial bending moment, shear forces, and changes in axial load distribution along pile length were induced. The findings from this study revealed that the building and pile responses are significantly influenced by the excavation depth.

scholarly journals Parametric Study of Pile Response to Side-by-Side Twin Tunneling in Stiff Clay

2020 ◽  
Vol 10 (2) ◽  
pp. 5361-5366
Author(s):  
N. Mangi ◽  
D. K. Bangwar ◽  
H. Karira ◽  
S. Kalhoro ◽  
G. R. Siddiqui
Keyword(s):  
Parametric Study ◽  
Three Dimensional ◽  
Bending Moment ◽  
Small Strain ◽  
Percentage Difference ◽  
Stiff Clay ◽  
The One ◽  
Numerical Parametric Study ◽  
Pile Response ◽  
Twin Tunnels

A three dimensional coupled-consolidation numerical parametric study was carried out in order to gain new insight of single pile response to side-by-side twin tunneling in saturated stiff clay. An advanced hypo plasticity (clay) constitutive model with small-strain stiffness was adopted. The effects of relative to the pile tunnel depths were investigated by simulating the twin tunnels near the pile at various depths of tunnels, namely near the pile shaft, adjacent to the pile toe, and below the pile toe. It was found that the second tunneling in each case resulted in a larger settlement than the one due to the first tunneling with a maximum percentage difference of 175% in the case of twin tunneling near the mid-depth of the shaft. This occurred due to the degradation of clay stiffness around the pile during the first tunneling. Conversely, the first tunneling-induced bending moment was reduced substantially during the second tunneling. The most critical location of twin tunnels relative to the pile was found to be below the pile toe.

ANALYSIS AND DESIGN OF G+4 RESIDENTIAL BUILDING USING ETABS

2021 ◽  
Vol 5 (12) ◽  
Author(s):  
Chinmay Padole ◽  
Samiksha Bansod ◽  
Taniya Sukhdeve ◽  
Abhishek Dhomne ◽  
Maheshwari Nagose ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Residential Building ◽  
Shape Modelling ◽  
Analysis And Design ◽  
Design Procedures ◽  
High Rise ◽  
Building Systems ◽  
Dynamic Loadings ◽  
Storey Building

ETABS stands for Extended Three-Dimensional Analysis of Building Systems. ETABS is commonly used to analyze: Skyscrapers, concrete structures, low and high rise buildings, and portal frame structures. The case study in this paper mainly emphasizes on structural behavior of multi-storey building for different plan configurations like rectangular, C, L and I-shape. Modelling of 15-storeys R.C.C. framed building is done on the ETABS software for analysis ETABS issue, for analysis and design for building systems. ETABS features are contain powerful graphical interface coupled with unmatched modeling, analytical, and design procedures, all integrated using a common database. STAAD and ETABS both of the software are well equipped and very much capable of handling different shape of the structures, static and dynamic loadings and different material properties.

scholarly journals EFFICIENT THREE-DIMENSIONAL MODELLING OF HIGH-RISE BUILDING STRUCTURES

2013 ◽  
Vol 19 (6) ◽  
pp. 811-822 ◽  
Author(s):  
Mohammed Jameel ◽  
A. B. M. Saiful Islam ◽  
Mohammed Khaleel ◽  
Aslam Amirahmad
Keyword(s):  
Three Dimensional ◽  
Shear Walls ◽  
Shear Wall ◽  
Frame Structure ◽  
Building Structures ◽  
Structural Behaviour ◽  
High Rise ◽  
Structural Responses ◽  
Wall Openings ◽  
Storey Building

A multi-storey building is habitually modelled as a frame structure which neglects the shear wall/slab openings along with the inclusion of staircases. Furthermore, the structural strength provided by shear walls and slabs is not precisely incorporated. With increasing building height, the effect of lateral loads on a high-rise structure increases substantially. Inclusion of shear walls and slabs with the frame leads to improved lateral stiffness. Besides, their openings may play imperative role in the structural behaviour of such buildings. In this study, 61 multi-storey building configurations have been modelled. Corresponding analyses are performed to cope with the influence of shear walls, slabs, wall openings, masonry walls and staircases in addition to frame modelling. The finite element approach is used in modelling and analysis. Structural responses in each elemental combination are evaluated through equivalent static and free vibration analyses. The assessment reveals that inclusion of only slab components with frame modelling contributes trivial improvement on structural performance. Conversely, the presence of shear wall slabs with frame improves the performance noticeably. Increasing wall openings decreases the structural responses. Furthermore, it is not recommended to model staircases in addition to frame–slab–shear wall modelling, unless the effect of wall openings and slab openings is adequately considered.

scholarly journals The Responses of an End-Bearing Pile to Adjacent Multipropped Excavation: 3D Numerical Modelling

2019 ◽  
Vol 5 (3) ◽  
pp. 552 ◽  
Author(s):  
Dildar Ali Mangnejo ◽  
Naeem Mangi
Keyword(s):  
Soft Clay ◽  
High Stress ◽  
Three Dimensional ◽  
Bending Moment ◽  
Small Strain ◽  
Ground Movement ◽  
Stress Regime ◽  
Moment Capacity ◽  
Negative Skin Friction ◽  
End Bearing Pile

It is well recognised that superstructure load is transferred to surrounding soil through piled foundation. Consequently, the high stress regime (stress bulb) is generated surrounding of the pile. On the other hand, the excavation in the ground inevitably results in the ground movement due to induced-stress release. These excavations are sometimes inevitable to be constructed adjacent to existing piled foundations. This condition leads to a big challenge for engineers to assess and protect the integrity of piled foundation. This research presents three-dimensional coupled consolidation analyses (using clay hypoplastic constitutive model which takes account of small-strain stiffness) to investigate the responses of an end-bearing pile due to adjacent excavation at different depths in soft clay. The effects of excavation depths (i.e., formation level) relative to pile were investigated by simulating the excavation near the pile shaft (i.e., case S) and next to (case T). It was revealed that the maximum induced bending moment in the pile after completion of excavation in all the cases is much less than the pile bending moment capacity (i.e. 800 kNm). Comparing the induced deflection of the end-bearing pile in the case T, the pile deflection in case S is higher. Moreover the piles in cases of S and T were subjected to significant dragload due to negative skin friction.

scholarly journals Effects of Construction Sequences and Volume Loss on Perpendicularly Crossing Tunnels

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Yanwei Zang ◽  
Penglu Gan ◽  
Jia-jia Yan ◽  
Shiming Liu ◽  
Zihai Yan
Keyword(s):  
Urban Areas ◽  
Rapid Development ◽  
Three Dimensional ◽  
Ground Surface ◽  
Stress Transfer ◽  
Bending Moment ◽  
Small Strain ◽  
Research Attention ◽  
The Past ◽  
Three Dimensional Finite Element

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.

scholarly journals Parametric Study on Unconnected Piled Raft Foundation Using Numerical Modelling

2020 ◽  
Vol 26 (5) ◽  
pp. 156-171
Author(s):  
Athraa Mohammed Jawad Alhassani ◽  
Ala Nasir Aljorany
Keyword(s):  
Axial Stress ◽  
Soil Layer ◽  
Structural Members ◽  
Element Analysis ◽  
Foundation Soil ◽  
High Rise ◽  
Piled Raft ◽  
Piled Raft Foundation ◽  
Raft Foundation ◽  
Pile Length

Piled raft is commonly used as foundation for high rise buildings. The design concept of piled raft foundation is to minimize the number of piles, and to utilize the entire bearing capacity. High axial stresses are therefore, concentrated at the region of connection between the piles and raft. Recently, an alternative technique is proposed to disconnect the piles from the raft in a so called unconnected piled raft (UCPR) foundation, in which a compacted soil layer (cushion) beneath the raft, is usually introduced.  The piles of the new system are considered as reinforcement members for the subsoil rather than as structural members. In the current study, the behavior of unconnected piled rafts systems has been studied numerically by means of 3D Finite Element analysis via ABAQUS software. The numerical analysis was carried out to investigate the effect of thickness and stiffness of the cushion, pile length, stiffness of foundation soil, and stiffness of bearing soil on the performance of the unconnected piled raft. The results indicate that when unconnected piles are used, the axial stress along the pile is significantly reduced e.g. the axial stress at head of unconnected pile is decreased by 37.8% compared with that related to connected pile. It is also found that the stiffness and thickness of the cushion, and stiffness of foundation soil have considerable role on reduction the settlement.

scholarly journals Assessing the effect of governing parameters of bearing capacity determination of small piled rafts on clay soil

2021 ◽  
Vol 14 (22) ◽  
Author(s):  
Shivanand Mali ◽  
Baleshwar Singh
Keyword(s):  
Shear Force ◽  
Bending Moment ◽  
Pile Spacing ◽  
Piled Raft ◽  
Pile Diameter ◽  
Piled Raft Foundation ◽  
Raft Foundation ◽  
Maximum Shear Force ◽  
Settlement Ratio ◽  
Pile Length

Abstract In the present study, a small piled raft foundation has been simulated numerically through PLAXIS 3-D software. The objective of this study was to investigate the effect of governing parameters such as pile length, pile spacing, pile diameter, and number of piles on the settlement and load-bearing behavior of piled raft, so as to achieve the optimum design for small piled raft configurations. An optimized design of a piled raft is defined as a design with allowable center and differential settlements and satisfactory bearing behavior for a given raft geometry and loading. The results indicated that, with increase in pile length, pile spacing, pile diameter, and number of piles, both the center settlement ratio and differential settlement ratio decreased. The load-bearing capacity of piled raft increased with increase in pile length, pile spacing, pile diameter, and number of piles. Furthermore, the percentage load carried by the piles increased as the pile length, pile spacing, pile diameter, and number of piles increased. The bending moment and shear force in corner pile are noted to be more, and they decreased towards the center pile. With increase in pile length, the maximum raft bending moment decreased, whereas the maximum shear force in the raft increased. Further, with increase in pile spacing, pile diameter, and number of piles, the maximum bending moment and maximum shear force in the raft increased. The optimum parameters for the piled raft foundation can be selected efficiently with the consideration of maximum bending moment and maximum shear force while designing the piled raft foundation. Thus, the results of this study can be used as guidelines for achieving optimum design for small piled raft foundation.

DYNAMIC ANALYSIS OF OFFSHORE PILES EMBEDDED IN ELASTOPLASTIC SOFT CLAY

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
Anis Mohamad Ali ◽  
Mohamad J. K. Essa ◽  
Abdulameer Qasim Hassan
Keyword(s):  
Soft Clay ◽  
Three Dimensional ◽  
Bending Moment ◽  
Pile Head ◽  
Finite Element Program ◽  
Head Displacement ◽  
Element Program ◽  
Pile Length ◽  
Elastoplastic Soil ◽  
Offshore Piles

This work deals with the dynamic behavior of offshore piles embedded in soft clay, and an attempt is made to estimate the critical embedded pile length. ABAQUS finite element program is used to simulate the problem. The soil was modeled as an elastic state and elastoplastic state and represented by cam-clay model. Three dimensional elements were used to represent the interaction between pile and soil, laboratory tests are used to obtain the real properties of soil and to describe interface. The results obtained are used to develop the elastic equation used by Matlock and Reese to calculate the critical embedded pile length for pile embedded in elastoplastic soil. Also, show that the critical embedded pile length is increased by about (20 % to 40 %) due to changing soil model from elastic to elastoplastic. The pile embedded in an elastoplastic soil is dependent on soil strength, interface properties and pile rigidity. The pile head displacement is increased about 90 % while the bending moment is deceased by 10 % at pile head.

Study the Impact of Differential Settlement on Frame Structure through Back-Analysis Method

2013 ◽  
Vol 671-674 ◽  
pp. 799-803
Author(s):  
Nan Jiang ◽  
Li Ming Huang
Keyword(s):  
Three Dimensional ◽  
Back Analysis ◽  
Bending Moment ◽  
Measured Data ◽  
Differential Settlement ◽  
Frame Structure ◽  
Analysis Method ◽  
Piled Raft Foundation ◽  
The Impact ◽  
Pile Length

This paper studied the impact of differential settlement of foundation on the inner force of architectural structure by applying back-analysis method. By taking the three-dimensional coactions system of upper structure-piled raft foundation-foundation with different pile length and different raft thickness as the research object, its differential settlement law of foundation under the effect of load was studied, which was combined with the practical measured data to fit the quadratic settlement surface equation of the foundation. The analysis demonstrated that the differential settlement of foundation will change the inner force of upper structure significantly, thus enabling most of construction components to produce great additional axial force, additional shearing force and additional bending moment, especially changing the additional inner force of corner post more evidently.

Issues on Design of Piled Raft Foundation

2018 ◽  
Vol 14 (1) ◽  
pp. 6057-6061 ◽  
Author(s):  
Padmanaban M S ◽  
J Sreerambabu
Keyword(s):  
Contact Area ◽  
Concrete Slab ◽  
Design Procedure ◽  
Bending Moment ◽  
Foundation Design ◽  
Detailed Review ◽  
Piled Raft ◽  
Piled Raft Foundation ◽  
Raft Foundation ◽  
Influencing Parameters

A piled raft foundation consists of a thick concrete slab reinforced with steel which covers the entire contact area of the structure, in which the raft is supported by a group of piles or a number of individual piles. Bending moment on raft, differential and average settlement, pile and raft geometries are the influencing parameters of the piled raft foundation system. In this paper, a detailed review has been carried out on the issues on the raft foundation design. Also, the existing design procedure was explained.

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