scholarly journals Laboratory Investigations into the Bearing Capacity of Straw Bales for Low-Rise Building Applications

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Baozhu Cao ◽  
Jun Hu ◽  
Yuansong Sun ◽  
Hongxin Nie
Keyword(s):  
Bearing Capacity ◽  
Rice Straw ◽  
Large Deformations ◽  
Mechanical Performance ◽  
Design Strength ◽  
Nonlinear Load ◽  
Uniaxial Load ◽  
Laboratory Investigations ◽  
Composite Walls ◽  
Straw Bale

Investigations were carried out to study the mechanical performance under uniaxial load of unplastered and plastered straw bales. Results from tests on 30 rice straw bales indicated nonlinear load-bearing properties with large deformations and anisotropy. Since the deformations observed did not conform to the current building code requirements, the evaluation of ultimate bearing capacity through the maximum axial vertical load was not possible. To obtain the design strength of rice straw bales in composite walls, further 21 specimens of plastered straw bales were also tested in compression. The permissible deformation of the straw bales was evaluated. It is noteworthy that the large deformability of straw bales can reduce the damage to structures after an earthquake. Consequently, the straw bale use can widely enhance the seismic performance of low-rise buildings.

scholarly journals Study on round rice straw bale wrapping silage technology and facilities

2018 ◽  
Vol 11 (4) ◽  
pp. 67-75
Author(s):  
Liqiao Li ◽  
◽  
Defu Wang ◽  
Xing Yang ◽  
Keyword(s):  
Rice Straw ◽  
Straw Bale

scholarly journals Damage Constitutive Model and Mechanical Performance Deterioration of Concrete under Sulfate Environment

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Peng Liu ◽  
Ying Chen ◽  
Zhiwu Yu ◽  
Zhaohui Lu
Keyword(s):  
Mechanical Properties ◽  
Bearing Capacity ◽  
Elasticity Modulus ◽  
Mechanical Performance ◽  
Sulfate Solution ◽  
Concrete Surface ◽  
Ultimate Bearing Capacity ◽  
Stress Strain ◽  
Before And After ◽  
Relationship Model

The effects of erosion mode, erosion age, and concentration of sulfate solution on mechanical properties of concrete were investigated. The dimensionless relationship model of the stress-strain of concrete on the basis of randomness was proposed. The variation of the elasticity modulus and Poisson’s ratio of the concrete surface attacked by sulfate was studied, and a novel method of using a superficial parameter to characterize the performance change of the concrete surface was recommended. The results showed that the dimensionless relationship model of stress-strain of concrete could be used to represent the variations of mechanical properties of concrete. The differences of load-displacement of concrete before and after sulfate attack were reflected as the change of curve’s slope and ultimate bearing capacity, and the slope of a straight section of the lateral and longitudinal strain curves of concrete surface also varied. The increment rates of ultimate bearing capacity of concrete attacked by 1% and saturated sulfate solution were about 30% and 10%, respectively. However, the decreasing ratio of the ultimate bearing capacity of concrete attacked by saturated sulfate solution was approximately 25%. The damage factor of the elasticity modulus of the concrete surface of C20 and C40 was 0.185 and −0.19, respectively. The obtained results could provide a support for investigating the variations of stress-strain relationship and mechanical performance of concrete under a sulfate environment.

scholarly journals Biocomposites from Rice Straw Nanofibers: Morphology, Thermal and Mechanical Properties

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2138 ◽  
Author(s):  
José Carlos Alcántara ◽  
Israel González ◽  
M. Mercè Pareta ◽  
Fabiola Vilaseca
Keyword(s):  
Rice Straw ◽  
Mechanical Performance ◽  
Cellulose Nanofibers ◽  
Nucleating Agent ◽  
Mechanical Analysis ◽  
Nanocomposite Films ◽  
Chemical Extraction ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
The Matrix

Agricultural residues are major potential resources for biomass and for material production. In this work, rice straw residues were used to isolate cellulose nanofibers of different degree of oxidation. Firstly, bleached rice fibers were produced from the rice straw residues following chemical extraction and bleaching processes. Oxidation of rice fibers mediated by radical 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) at pH 10 was then applied to extract rice cellulose nanofibers, with diameters of 3–11 nm from morphological analysis. The strengthening capacity of rice nanofibers was tested by casting nanocomposite films with poly(vinyl alcohol) polymer. The same formulations with eucalyptus nanofibers were produced as comparison. Their thermal and mechanical performance was evaluated using thermogravimetry, differential scanning calorimetry, dynamic mechanical analysis and tensile testing. The glass transition of nanocomposites was shifted to higher temperatures with respect to the pure polymer by the addition of rice cellulose nanofibers. Rice nanofibers also acted as a nucleating agent for the polymer matrix. More flexible eucalyptus nanofibers did not show these two phenomena on the matrix. Instead, both types of nanofibers gave similar stiffening (as Young’s modulus) to the matrix reinforced up to 5 wt.%. The ultimate tensile strength of nanocomposite films revealed significant enhancing capacity for rice nanofibers, although this effect was somehow higher for eucalyptus nanofibers.

scholarly journals Numerical simulation of complex tubular joints of Beijing New Airport Terminal C type column

2019 ◽  
Vol 138 ◽  
pp. 01001
Author(s):  
A Zhang ◽  
G Shangguan ◽  
Yanxia Zhang ◽  
Dinan Shao
Keyword(s):  
Numerical Simulation ◽  
Bearing Capacity ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Simulation Analysis ◽  
Economic Benefits ◽  
Tubular Joints ◽  
Airport Terminal ◽  
Stiffening Ribs ◽  
Final Optimization

The numerical simulation analysis of the two groups of fullscale complex tubular joints of the Beijing New Airport Terminal C type steel column under space static loading tests has been conducted by adopting software ABAQUS. The results obtained from the numerical simulation analysis consistent with those from the tests which enriched the research findings. Based on the research, mechanical performance of the joints has been carried out, the failure modes and ultimate bearing capacity of the joints with no stiffening ribs, three stiffening ribs and five stiffening ribs has been obtained. The numerical simulation results showed that, the bearing capacity of the joints without stiffening ribs were relatively low, the plastic failure of the main pipe was the major form of the destruction and the safety performance were too poor to meet the actual needs of the project. The bearing capacity of the joints significantly improved with the stiffening ribs set inside and the destruction changed to the connection of the main tubular and the branch, which means that the stress of the joints has been obviously improved by the setting of the stiffening ribs and was able to meet the needs of Beijing New Airport Terminal C type column. Through the comparative analysis of the stiffening ribs setting, it can be found that the bearing capacity of the joints were similar between the three and five stiffening ribs, considering the construction difficulty and economic benefits, three stiffening ribs has been selected as the final optimization result.

Research on Concrete-Filled Rectangular Steel Tube Stiffeners and Axial Compression Bearing Capacity

2014 ◽  
Vol 1065-1069 ◽  
pp. 1092-1096 ◽  
Author(s):  
Gao Cheng ◽  
Yong Jian Liu ◽  
Lei Jiang
Keyword(s):  
Bearing Capacity ◽  
Mechanical Performance ◽  
Compressive Load ◽  
Steel Tube ◽  
Simple Construction ◽  
The Core ◽  
Steel Bar ◽  
Stiffening Ribs ◽  
Reinforcement Measures ◽  
Core Concrete

Concrete-filled rectangular steel tube four sides restraint effect on the core concrete was weaker than the corner, which made the effect not significant. The paper studied a new kind of stiffening rib –PBL stiffener to strengthen restraint effect of concrete-filled rectangular steel tube , and evaluated its advantages compared with other stiffening ribs. 9 PBL stiffened concrete-filled rectangular steel tube columns under axial compressive load were tested. It also collected the test with other stiffened rids, such as straight ribs, binding bars, knee brace, steel reinforcement cage, steel bar stiffeners, saw tooth shaped stiffeners, stitching straight stiffeners and no rib concrete filled rectangular steel tube to compare. It evaluated increasing coefficient of bearing capacity by stiffening ribs. The results showed that: the PBL stiffeners and binding bar of concrete-filled rectangular steel tube bearing capacity was greater than other reinforcement measures by more than 20%; PBL stiffener could be a new prominent type of stiffener because of its excellent mechanical performance and simple construction.

scholarly journals Effects of Different Interface Forms on Mechanical Properties of Steel Self-Compacting Concrete Composite Beams

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Chengzhi Wang ◽  
Xin Liu ◽  
Wei Liu ◽  
Zhiming Li
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Bearing Capacity ◽  
Composite Structure ◽  
Mechanical Performance ◽  
Complex Structure ◽  
Self Compacting Concrete ◽  
Element Analysis ◽  
Shear Connectors ◽  
Fea Model

In the water resources allocation project in Pearl River Delta, in order to optimize the structural design, the deep buried tunnel adopts the composite lining structure. However, the weakest link in a complex structure is the connection between two different interfaces. This paper reports the findings of an experimental study that was undertaken to investigate the interface mechanical performance of steel self-compacting concrete composite structure subjected to cyclic loads. In this study, different shear connectors are considered, and six different specimens were designed and tested, respectively. The test is used to research the effect of the different shear connectors on the bearing capacity and interface mechanical properties of composite structure in an experimental study. According to these test results, a detailed analysis was carried out on the relationships, such as the stress-strain and load-displacement relationships for the specimen. These tests show that the shear connectors will significantly enhance the bearing capacity and interface mechanical properties of the composite structure. Among them, the comprehensive performance of the specimens using the stud-longitudinal ribs shear connectors is the best. Additionally, a finite element analysis (FEA) model was developed. The comparison of the simulation results with the experimental results shows that this FEA is applicable for this type of experiment.

Hysteretic Behavior of Composite Vertical Connection Structures used in Prefabricated Shear Wall Systems

2020 ◽  
Vol 20 (06) ◽  
pp. 2040007
Author(s):  
Limeng Zhu ◽  
Haipeng Yan ◽  
Po-Chien Hsiao ◽  
Jianhua Zhang
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
High Strength Steel ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Shear Walls ◽  
High Strength ◽  
Shear Wall ◽  
Hysteretic Behavior ◽  
Design Standards

An innovative composite vertical connecting structure (CVC) with capacity carrying and energy-dissipating ability is proposed in this study, which could be used in prefabricated composite shear wall structural systems to enhance the resilience and seismic performance of structural system. The CVC structure is mainly composed of three parts, including the connecting zone, the capacity bearing zone characterized by high strength and elastic deforming ability, and the energy-dissipating zone assembled by replaceable metal dampers. The low-yield strength steel and high-strength steel are used, respectively, for the metal dampers in the energy-dissipating zone and the concrete-filled high-strength steel tubes in the bearing capacity zone to enhance the energy dissipation and self-centering abilities of CVC structures. The working mechanism is analyzed and validated through finite element models built in ABAQUS. The hysteretic behavior is simulated to evaluate their performance. First, the metal dampers are designed. The theoretical and finite elemental parametric analysis are carried out. According to the simulation results, the “Z-shaped” metal dampers exhibit better energy-dissipating ability than the rectangular shape, in which the “Z-shaped” metal dampers with 45∘ show the best performance. Simultaneously, the results of the models calculated by the finite element method and theoretical analysis work very well with each other. Furthermore, seven FE models of shear walls with CVC structures are designed. Monotonic and cyclic loading simulations are conducted. The failure modes and comprehensive mechanical performance are investigated and evaluated according to their calculated force–displacement curves, skeleton curves, and ductility coefficients. The results indicate that the CVC structure delivered preferable lateral-bearing capacity and displacement ductility. Finally, according to available design standards, the lateral stiffness of CVC structures could be conventionally controlled and some practical design recommendations are discussed.

Numerical Simulation on the Mechanical Performance of the Wind Generator Latticed Concrete-Filled Steel Tubular Tower

2014 ◽  
Vol 578-579 ◽  
pp. 751-756
Author(s):  
Bin Li ◽  
Qun Hui Zhang ◽  
Chun Yan Gao
Keyword(s):  
Finite Element ◽  
Aspect Ratio ◽  
Bearing Capacity ◽  
Failure Mode ◽  
Mechanical Performance ◽  
Great Influence ◽  
Local Buckling ◽  
Ultimate Bearing Capacity ◽  
Thickness Ratio ◽  
Stiffness Ratio

Nonlinear finite element parameters analysis on the lattice type steel pipe concrete wind turbine tower, it shows the entire process of load bearing, failure mode and ultimate bearing capacity, researches on the influence law of aspect ratio, form of tower webs, tower diameter to thickness ratio and web member stiffness to tower column stiffness ratio on the ultimate bearing capacity and tower failure mode. The finite element analysis results shows that the tower aspect ratio λ, the diameter-thickness ratio γ of tower columns and the increase of stiffness ratio β between web members and tower columns has great influence on ultimate bearing capacity and failure mode, while the form of webs has small influence on that. with the increase of tower aspect ratio λ, the decrease of diameter-thickness ratio γ of tower columns and the increase of stiffness ratio β between web members and tower columns, the ultimate bearing capacity of this kind of latticed towers increase, the failure mode changed from Web local buckling to The combined damage of Web local buckling and the tension tower yield. This paper suggests that in the design of wind turbulent generator tower, the tower aspect ratio λ should be best controlled at 1/9, the bottom layers of this kind of tower should best use the re-divided web members, and other web member forms used on above layers, the diameter-thickness ratio γ of tower column should be taken less than 30, and the stiffness ratio β between webs and columns should be controlled less than 0.05 in order to avoid damage occurring on the tower columns earlier than the webs. The results can provide evidence for the engineering design.

Experimental and Theoretical Study on Seismic Behavior of Profiled Steel Sheet-Bamboo Plywood Composite Walls

2010 ◽  
Vol 113-116 ◽  
pp. 2246-2250 ◽  
Author(s):  
Wang Li Zhang ◽  
Yu Shun Li ◽  
Huang Ying Shen ◽  
Tian Yuan Jiang ◽  
Zhen Wen Zhang
Keyword(s):  
Bearing Capacity ◽  
Steel Sheet ◽  
High Strength ◽  
Static Tests ◽  
Seismic Properties ◽  
Earthquake Resistant ◽  
Steel Composite ◽  
Composite Wall ◽  
Composite Walls ◽  
Simplified Mechanical Model

In order to promote building structure to be environmental friendly, light-weight and high-strength, a novel bamboo-steel composite wall is proposed. The composite wall is made up by sticking two pieces of bamboo plywood on the faces of a piece of profiled steel sheet utilizing structural glue. Taking thickness of the bamboo plywood and thickness and corrugation-height of the profiled steel sheet as variables, quasi-static tests were carried out on 5 specimens. Based on experimental phenomena and data, their earthquake resistant properties such as horizontal bearing capacity, ductility and energy dissipation and failure mechanism are analyzed. The results show that the bamboo plywood and profiled steel sheet can effectively work together, the composite walls possess wonderful seismic properties, and that changes of thickness or corrugation-height of profiled steel sheet make very sharp differences to the properties of the walls. Finally, a simplified mechanical model and calculation method for horizontal bearing capacity are proposed according to hysteresis curves within elastic range of these walls. The calculated values match well with the experimental ones.

Reinforcement Technology of Space Grid Structure for Reconstruction of Shandong Qufu Xingtan Theater

2011 ◽  
Vol 243-249 ◽  
pp. 5487-5490
Author(s):  
Lian Fen Weng ◽  
Ming Gong ◽  
Zhen Hua Liu ◽  
Xiao Bei Wang
Keyword(s):  
Bearing Capacity ◽  
Double Layer ◽  
Mechanical Performance ◽  
Slenderness Ratio ◽  
Social Benefit ◽  
Grid Structure ◽  
Construction Period ◽  
Structure System ◽  
Space Grid ◽  
Temporary Structure

Shandong Qufu Xingtan Theater, originally built for an open-air theater, was designed as a one-time temporary structure with bolt ball junction double-layer regular pyramids grid structure roofing system. Because of the transformation of open-air structure system to an enclosed construction, some members of the space grid structure can not meet the required bearing capacity. According to the mechanical performance of space grid structures, the reinforcement methods of “circular steel jacketing” and “lateral support” are conducted, which are based on the analysis of the stress and stability characteristics of different grid members. By using the methods given above, the stress and slenderness ratio is decreased. The results indicate that the two reinforcement methods can reduce the difficulty in construction, shorten the construction period, and gain good economic and social benefit.

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