Moment-less Arches for Reduced Stress State

2021 ◽  
Author(s):  
Wanda Lewis ◽  
Justin Russell ◽  
Thomas Li
Keyword(s):  
Load Transfer ◽  
Solution Process ◽  
Analytical Form ◽  
Load Resistance ◽  
Shape Prediction ◽  
Axial Forces ◽  
Hoover Dam ◽  
Resistance Moment ◽  
Permanent Load ◽  
Arch Forms

This paper presents a study of two-pin arches of constant cross-section that are moment-less under statistically prevalent (permanent) load. The arches are defined by analytical form-finding previously reported in [1]. The work provides guidance regarding the solution process, and expressions for reactions and axial forces. New analytical results include the derivation of the arch length, and a method for finding co-ordinates of individual arch segments in pre-fabricated construction. The accuracy of the shape prediction for inextensible moment-less arches is good, compared to the results from elastic models. Case studies report on medium and large-span arches, with the latter resembling the iconic Hoover Dam arch. Comparative studies of the moment-less and conventional arch forms (mostly of parabolic configuration), are carried out using permanent and variable loads. Additionally, the Hoover Dam arch is analysed for a discrete load transfer from the deck. Circular arches are analysed for the permanent load only, and are shown to be extremely inefficient in load resistance. Moment-less arches are found to provide a minimal stress response to loading and require least amount of material – a feature observed in natural objects. These characteristics are important from a durability perspective – a key concern for our future infrastructure.

Numerical investigation on load transfer mechanism of bonded post-tensioned concrete beam-column substructures against progressive collapse

2020 ◽  
pp. 136943322098165
Author(s):  
Kai Qian ◽  
Hai-Ning Hu ◽  
Yun-Hao Weng ◽  
Xiao-Fang Deng ◽  
Ting Huang
Keyword(s):  
Prestressed Concrete ◽  
Load Transfer ◽  
Numerical Models ◽  
Progressive Collapse ◽  
Load Resistance ◽  
Catenary Action ◽  
Parabolic Profile ◽  
Arch Action ◽  
Column Removal Scenario ◽  
Post Tensioned

This paper presents the high-fidelity finite-element-based numerical models for modeling the behavior of prestressed concrete (PC) beam-column substructures to resist progressive collapse under column removal scenario. After careful calibration against data, the validated numerical models are further employed to shed light on the influence of bonded post-tensioned tendons (BPT) with a parabolic profile on the load transfer mechanisms of PC frames against progressive collapse. The effects of parameters, including initial effective prestress, profile of tendon and lateral constraint stiffness at the beam ends, are also investigated. The study shows that, due to the presence of prestressed tendons, the mobilization of compressive arch action in the beam at small deflections demands stronger lateral constraints, and the ultimate load resistance of PC beam-column substructures depends on combined catenary action from non-prestressed reinforcement and BPT at large deflections. For a given constraint stiffness, the initial effective prestress of BPT has less significant effect on the overall structural behavior. For prestressed tendon, a straight profile usually employed in structural strengthening can improve the initial structural stiffness and yield strength, but is less effective in enhancing the ultimate resistance against progressive collapse than the parabolic profile.

Responses of single piles to tunneling-induced soil movements in sandy ground

2007 ◽  
Vol 44 (10) ◽  
pp. 1224-1241 ◽  
Author(s):  
Kuo-Hui Chiang ◽  
Chung-Jung Lee
Keyword(s):  
Load Transfer ◽  
Bending Moment ◽  
Test Results ◽  
Axial Forces ◽  
Depth Ratio ◽  
Sandy Ground ◽  
Single Piles ◽  
Pile Settlement ◽  
Ground Loss ◽  
Soil Movements

The responses of single piles under various working loads to nearby tunneling were investigated using centrifuge model tests. First, the tunneling-induced soil movements and the tunnel stability in saturated sandy ground were examined. Two instrumented piles with penetration depths of 27 m were located either side of, and at various distances from, tunnels embedded at depths with various cover-to-diameter ratios, and used to measure the bending moments and axial forces at various depths for various ground loss ratios during tunneling simulations. The test results show that in the case of shallow tunneling near a long pile the unit skin frictions on the pile from the tunnel axis to an elevation of 1.5 tunnel diameters above the tunnel axis rapidly decrease with increases in the ground loss ratio. A significant degradation of the end bearing capacity results in a large settlement of the pile if the pile tip is near the tunnel. The depth ratio was found to be a significant influence on the bending moment profiles along the piles, but both the depth ratio and the working loads on the pile head determine the axial load profile and the pile settlement. A mechanism for pile load transfer during new tunneling is proposed to enable construction engineers to prevent structure failure in piles and excessive pile settlement.

scholarly journals Stabilization of Slopes of Sandy Soils by Using Geosynthetics

2021 ◽  
Vol 1197 (1) ◽  
pp. 012081
Author(s):  
Tudumu Viveka ◽  
Namburu Sandeep Kumar ◽  
K. Shyam Chamberlin
Keyword(s):  
Slope Failure ◽  
Load Transfer ◽  
Load Resistance ◽  
Internal Resistance ◽  
Soil Reinforcement ◽  
Cohesionless Soils ◽  
Angle Of Internal Friction ◽  
Lateral Load Resistance ◽  
Shear Box ◽  
Cohesion Less Soil

Abstract This paper intended on the interactive performance of geo-synthetics in slope stabilization of non-cohesive soils. Presently, geo-synthetics are performing crucial role in geo-technical uses for reinforcing of soils for slope of stabilization, soil reinforcement for foundations, R E walls for highway and flyover construction etc. Usually, cohesion less soil is ideal for backfills of the embankments as of its exceptional drainage properties, at a low-level hydrostatic pressure built-up on slopes and excessive internal resistance owing to friction and interlocking. To research this property of geo-synthetics, relative density and shear box tests are done on the soil by varying geosynthetics for assessment of the shear parameters of sample. The mosquito reinforcement net as reinforcement on cohesionless soils, improvement in the angle of internal friction of the soil was observed by twenty-two percentage that the shear strength to be improved by 26.5%. So, the soil’s lateral load resistance or load transfer capacity improved to prevent the slope failure thereby saves the entire structure.

scholarly journals USING OF MULTILAYER NEURAL NETWORKS FOR THE SOLVING SYSTEMS OF DIFFERENTIAL EQUATIONS

2021 ◽  
pp. 81-88
Author(s):  
Natalia Marchenko ◽  
Ganna Sydorenko ◽  
Roman Rudenko
Keyword(s):  
Neural Networks ◽  
Differential Equations ◽  
Loss Function ◽  
Initial Conditions ◽  
Solution Process ◽  
Analytical Form ◽  
Individual Values ◽  
Systems Of Differential Equations ◽  
Solving Equations ◽  
Multilayer Neural Networks

The article considers the study of methods for numerical solution of systems of differential equations using neural networks. To achieve this goal, thefollowing interdependent tasks were solved: an overview of industries that need to solve systems of differential equations, as well as implemented amethod of solving systems of differential equations using neural networks. It is shown that different types of systems of differential equations can besolved by a single method, which requires only the problem of loss function for optimization, which is directly created from differential equations anddoes not require solving equations for the highest derivative. The solution of differential equations’ system using a multilayer neural networks is thefunctions given in analytical form, which can be differentiated or integrated analytically. In the course of this work, an improved form of constructionof a test solution of systems of differential equations was found, which satisfies the initial conditions for construction, but has less impact on thesolution error at a distance from the initial conditions compared to the form of such solution. The way has also been found to modify the calculation ofthe loss function for cases when the solution process stops at the local minimum, which will be caused by the high dependence of the subsequentvalues of the functions on the accuracy of finding the previous values. Among the results, it can be noted that the solution of differential equations’system using artificial neural networks may be more accurate than classical numerical methods for solving differential equations, but usually takesmuch longer to achieve similar results on small problems. The main advantage of using neural networks to solve differential equations` system is thatthe solution is in analytical form and can be found not only for individual values of parameters of equations, but also for all values of parameters in alimited range of values.

Method of Designing a Plate-like Ultra High-rise Building

2018 ◽  
Author(s):  
Shoko Okamura ◽  
Kei Muto
Keyword(s):  
Structural Design ◽  
Load Resistance ◽  
Test Results ◽  
High Rise ◽  
High Rise Building ◽  
Axial Forces ◽  
Column Joint ◽  
Strong Winds ◽  
And Performance

<p>This paper describes the method of structural design of a plate-like ultra high-rise building, taking the Shinjuku Toho Building as an example. In particular the major problems in the structural design of this building are described, namely ensuring safety during earthquakes, ensuring habitability during strong winds, and ensuring the load resistance of the columns that are subject to large axial forces. Also, the test results and performance of an "improved non-scallop method" for beam- column joint are described. Finally the method of structural designing "Godzilla’s Head" is described.</p>

The Assessment of Pipeline Integrity in Geohazard Areas Using ILI Data

2013 ◽  
Author(s):  
Andy Young ◽  
Aaron Lockey
Keyword(s):  
Load Transfer ◽  
Force Component ◽  
Mapping Data ◽  
Transition Zones ◽  
Future Performance ◽  
Analysis Process ◽  
Axial Forces ◽  
Mapping Techniques ◽  
Key Aspects ◽  
Soil Pipe

In-line inspection by inertial mapping techniques is an essential tool for pipeline operators in areas susceptible to geohazards. The detection of previously unknown movements can provide early warning of the presence of a hazard. Positional change and the nature of the loading process can be monitored using the results of multiple inspections over time. Structural modelling is required to fully evaluate the integrity of the pipeline and whether a failure condition is being approached. Finite element techniques can be used, including the effects of soil-pipe interaction, axial forces and operational loads. This enables the prediction of future performance, based on trends from multiple inspections, so that mitigation or intervention methods are efficiently designed and scheduled. This paper considers some key aspects of the analysis process. The use of ILI mapping data to detect small movements below the tool measurement tolerance is examined. The importance of structural analysis is demonstrated by consideration of the axial force component. The inherent variability of the soil surrounding the pipe and its influence on the load transfer effects is illustrated, together with the issues of significant interaction within the transition zones of landslides or faults.

scholarly journals An Analytical Study of Square CFT Columns in Bracing Connection Subjected to Axial Loading

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Jianrong Pan ◽  
Peng Wang ◽  
Yanjun Zheng ◽  
Zhan Wang ◽  
Deming Liu
Keyword(s):  
Axial Load ◽  
Load Transfer ◽  
Numerical Models ◽  
Axial Loading ◽  
Steel Tube ◽  
Gusset Plate ◽  
Composite Action ◽  
Axial Forces ◽  
Cft Column ◽  
Core Concrete

This paper presents the behavior of square concrete-filled tubular (CFT) columns with different penetrating gusset plates under axial load. Load transfer mechanism in the CFT columns including load distribution between gusset plate and core concrete and composite action of the gusset plate and steel tube was investigated. Experimental results showed that the axial load can be transferred from the bottom edge, ribs, and the hole of the gusset plate to core concrete through the bearing mechanism. Adding ribs or a hole on the gusset plate can efficiently facilitate load transmission and improve the composite action. Numerical models were established to determine the distribution of axial forces among members in the square CFT column. Then, revised coefficients of elastic modulus for the square CFT column with the gusset plate were proposed.

Geogrid-Reinforced Pile-Supported Railway Embankments

2005 ◽  
Vol 1936 (1) ◽  
pp. 221-229 ◽  
Author(s):  
Jie Huang ◽  
Jie Han ◽  
James G. Collin
Keyword(s):  
Load Transfer ◽  
Soft Soil ◽  
Three Dimensional ◽  
Field Measurements ◽  
Failure Criteria ◽  
Organic Soils ◽  
Lagrangian Analysis ◽  
Modeling And Analysis ◽  
Axial Forces ◽  
Lateral Displacements

Piles or columns have been used successfully in combination with geosynthetics to support embankments over soft soil. The inclusion of geosynthetic reinforcement over piles enhances load transfer from soil to piles, reduces total and differential settlements, and increases slope stability. It creates a more economical alternative than that without the geosynthetic. An existing geosynthetic-reinforced pile-supported embankment in Berlin was selected for numerical modeling and analysis. This embankment was constructed to support railways over deep deposits of peat and soft organic soils. Precast piles and caps were installed with a load transfer platform formed by three layers of geogrid and granular materials installed between the piles and the embankment fill. Instrumentation was installed to monitor the settlements of the embankment and the strains in the geogrid layers over time. A finite difference method, incorporated in the fast Lagrangian analysis of continua three-dimensional software, was used to model this embankment. In the numerical analysis, piles were modeled with pile elements, and caps were modeled as an elastic material. Geogrid elements built in the software were used to represent the geogrid reinforcement. Embankment fill, soft soil, firm soil, and platform fill material were modeled as linearly elastic perfectly plastic materials with Mohr–Coulomb failure criteria. The embankment was built by a number of lifts to simulate its construction. Numerical results and comparisons with field measurements on the vertical and lateral displacements, the tension along the reinforcement, and the axial forces and moments on piles are presented.

Research on the resistance of modified bolted connection under progressive collapse scenario

2021 ◽  
pp. 136943322110048
Author(s):  
Xian Rong ◽  
Xiuchen Xu ◽  
Yansheng Du
Keyword(s):  
Failure Modes ◽  
Load Transfer ◽  
Progressive Collapse ◽  
Load Resistance ◽  
Conventional Technique ◽  
Finite Element Models ◽  
Bolted Connection ◽  
Structural Resistance ◽  
Chord Rotation ◽  
Simplified Mechanical Model

Beam-to-column connection configurations, such as welded, bolted, and mixed welded-bolted connections, play an important role in structural resistance and ductility under middle column-removal scenarios. This paper illustrates full-scale laboratory tests of two steel frame assemblies with different connection details under the progressive collapse scenario. One specimen adopts the modified conventional technique which has reinforced welded flange-bolted web connection (SC-WR), and the other specimen uses a slotted-hole connection based on the former (SC-WB). The failure modes, load transfer mechanism, and vertical resistance are analyzed in the test. Both connection configurations exhibit satisfactory load resistance and ductility supply. Specimen SC-WB shows the higher ultimate vertical capacity and greater chord rotation at later catenary stage due to a sufficient redistribution of the stress with the modified bolted shear tab. Moreover, finite element models (FEM) are developed and validated against the test data. FEM can accurately simulate the mechanical behaviors and the failure of specimens, which can provide an effective reference for the beam-to-column connection configurations in similar working conditions. Finally, a simplified mechanical model is exhibited in accordance with the experimental and numerical results to reveal the effect of the catenary mechanism. This result suggests that the duration of the catenary mechanism, rather than the magnitude of the axial force, plays an essential role in the resistance of vertical load.

scholarly journals Checking the Stability Criteria of Multi-Storied Building by Varying Opening Area Percentages in Shear Wall Used in Periphery with Seismic Zone III

2021 ◽  
Vol 9 (11) ◽  
pp. 127-135
Author(s):  
Mr. Prashant Sharma
Keyword(s):  
Response Spectrum ◽  
Shear Walls ◽  
Shear Wall ◽  
Load Resistance ◽  
Response Analysis ◽  
Seismic Zone ◽  
Wall Area ◽  
Axial Forces ◽  
Cost Cutting ◽  
The Cost

Abstract: To decrease the overall cost of the project, it is highly recommended dropping the cost in different manners. To make economic structure, structure without losing the stiffness standards and the cost cutting should be done at every construction stages. The dual systems in building structure consist of structural walls and moment resisting frames. The walls are made up of RCC, which is expensive material. The purpose of current study is to discover the effect of reducing shear wall area in multistorey building to decrease cost. The buildings are provided with shear walls to improve the lateral load resistance. Post parametric analysis results shows that, the reduction in shear wall area should be modified to a certain limit up to 20 % for cost cutting. But in this study, the opening areas of shear wall are increased above 20% to 36.75% and verify the results of post analysis. In this study 8 cases are analysed with 0%, 11%, 14.20%, 20%, 33.20%, 29.05%, 35%, & 36.75% opening in shear wall and analysis is perform by Response Analysis Method of dynamic analysis using Staad.pro V8i software in Zone III of multistorey building (G+18). The effects of opening in the wall are studied by considering the moments, shear, and torsion, and axial forces in the beams and columns. It is observed that after a certain percentage of shear opening in walls the building fails in the drift at a certain height. To resolve this problem the flared area of height 0.5 m at the height of failure is provided to counteract the effect of drift. It was observed that by the introduction of shear belt the drift reduces which made the structure stable. Finally in this study, the opening of shear wall area is increased up to 35% and concrete area is reduced 1170.20 m2 , which is 534.2m2 more than the previous studies. Keywords: Shear Wall, Opening Area, Multi-storeyed Building, Seismic effects, Response Spectrum Method

Sign in / Sign up

Export Citation Format

Share Document