scholarly journals Experimental Study and Numerical Simulation on Mechanical Properties of the Bottom Plate in the Assembled Composite Slab with Additional Steel Trusses

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Xiuying Yang ◽  
Yuzhuo Wang ◽  
Yongxin Liu ◽  
Zhenyu Wei
Keyword(s):  
Crack Resistance ◽  
Limit State ◽  
Load Level ◽  
Bottom Plate ◽  
Composite Slab ◽  
Static Test ◽  
Service Limit State ◽  
New Type ◽  
Transverse Steel ◽  
Steel Trusses

The composite slab with steel trusses is composed of precast bottom plate and cast-in-place concrete. In engineering applications, cracks often appear in the bottom plate before casting the upper concrete, which even leads to the failure of the composite slab. To improve the crack resistance of the slab, a composite slab with additional steel trusses is proposed; that is, on the basis of the original longitudinal steel trusses, the transverse steel trusses are added. Static test and numerical analysis were carried out on the bottom plate of the new type of composite slab with the additional transverse steel trusses. The experimental and analytical results show that the load level of the plate with additional steel trusses can be increased by 33% under the normal service limit state; the deflection of the plate is significantly reduced and the crack development is effectively controlled, which illustrates that the new type of composite slab can improve the bearing capacity, increase the bending stiffness, and enhance the crack resistance effectively.

Strain Analysis of Composite Frame Joints with Double Side Penetrated Diaphragms

2012 ◽  
Vol 166-169 ◽  
pp. 3277-3281
Author(s):  
Min Tong
Keyword(s):  
Stress Distribution ◽  
Strain Analysis ◽  
Steel Tube ◽  
Core Region ◽  
Steel Beam ◽  
Static Test ◽  
The Core ◽  
Composite Frame ◽  
Joint Connection ◽  
New Type

Abstract. Connection joint with penetrated diaphragm, which is better for the stressing state of the welding connection, is a new type joint for the beam and column connection. Static test and pseudo-static test are put to 17 crossing joints. The stress distribution of the steel beam and the penetrated diaphragm are discussed. The experiment shows that the penetrated diaphragm transfer most tension force of the steel beam’s upper flange to the core region of the joint, which could effectively decrease the stress and strain gradient within the connection area of the steel beam’s upper flange and steel tube column. As the result, the shear force of the core region is decreased. The front weld is avoided being surfing great tension. The ductility of the joint and the energy dissipation capacity of the structure are then increased. The type and the size of the penetrated diaphragm show great affection to the stress distribution of steel beam and penetrated diaphragm. The study achievement enriches the joint connection type of the composite structure with concrete- filled steel tube.

Assessment and propagation of mechanical property uncertainties in fatigue life prediction of composite laminates

2018 ◽  
Vol 52 (24) ◽  
pp. 3381-3398 ◽  
Author(s):  
Oscar Castro ◽  
Kim Branner ◽  
Nikolay Dimitrov
Keyword(s):  
Fatigue Life ◽  
Composite Laminates ◽  
Fatigue Behavior ◽  
Limit State ◽  
Turbine Blades ◽  
Laminated Composite ◽  
Load Level ◽  
Wind Turbine Blades ◽  
Laminated Composite Materials ◽  
Fatigue Limit State

A probabilistic model for estimating the fatigue life of laminated composite materials considering the uncertainty in their mechanical properties is developed. The uncertainty in the material properties is determined from fatigue coupon tests. Based on this uncertainty, probabilistic constant life diagrams are developed which can efficiently estimate probabilistic ɛ-N curves at any load level and stress ratio. The probabilistic ɛ-N curve information is used in a reliability analysis for fatigue limit state proposed for estimating the probability of failure of composite laminates under variable amplitude loading cycles. Fatigue life predictions of unidirectional and multi-directional glass/epoxy laminates are carried out to validate the proposed model against experimental data. The probabilistic fatigue behavior of laminates is analyzed under constant amplitude loading conditions as well as under both repeated block tests and spectral fatigue using the WISPER, WISPERX, and NEW WISPER load sequences for wind turbine blades.

scholarly journals Analysis of the Crack Resistance of the Cement Stone and Roche

2019 ◽  
Vol 50 (2) ◽  
pp. 124-131
Author(s):  
Vladimir Erofeev ◽  
Irina Maksimova ◽  
Nikolay Makridin ◽  
Alexey Bulgakov ◽  
Salman Al-Dulaimi
Keyword(s):  
Crack Resistance ◽  
Influencing Factor ◽  
Limit State ◽  
Practical Importance ◽  
Cement Composite ◽  
Material Structure ◽  
Cement Stone ◽  
Professional Literature ◽  
Actual Strength ◽  
New Generation

The crack resistance is the most important parameter of strength. It characterizes the ability of a material structure to resist the beginning of the movement and development of cracks at mechanical and other force impacts and is the most important parameter of the limit state of the structure. In this regard, the evaluation of parameters of the mechanics of rocks, used as fillers (dispersed phase) and the cement stone (matrix phase) for concrete, influencing factor of the actual strength of the cement composite, is not only of theoretical interest, but also of great practical importance, since the issues in regards to the problem of choosing fillers are very poorly addressed in the professional literature, especially re the new generation of concretes.

scholarly journals Calibration of models for pile settlement analysis using 64 field load tests

2008 ◽  
Vol 45 (1) ◽  
pp. 59-73 ◽  
Author(s):  
L. M. Zhang ◽  
Y. Xu ◽  
W. H. Tang
Keyword(s):  
Hong Kong ◽  
Prediction Models ◽  
Limit State ◽  
Design Guidelines ◽  
Load Level ◽  
Soil Parameters ◽  
Model Bias ◽  
Nonlinear Load ◽  
Settlement Prediction ◽  
Pile Settlement

Due to the presence of uncertainties, errors inevitably arise with the estimations of pile settlement. To properly consider serviceability requirements in limit state design, it is necessary to characterize the performance of commonly used settlement prediction models. In this work, information from 64 cases of long driven steel H-piles from field static loading tests in Hong Kong is utilized to evaluate the errors of three settlement prediction models for single piles: two elastic methods and a nonlinear load–transfer method. Commonly adopted soil parameters recommended in two Hong Kong design guidelines are used to reflect the uncertainty arising from evaluation of soil properties. The model error is represented by a bias factor. A conventional statistical analysis was first conducted to study the variability of model bias. A regression analysis method was then proposed as a supplemental analysis of model bias when only limited test data were available or when the measured settlement data distribute in a large range. Both methods result in very similar mean biases. The mean bias of each prediction model tends to vary with the load level and the bearing stratum at the pile toe; while the coefficient of variation of model bias only varies in narrow ranges.

Dynamic Characteristics of a New Space Beam String Structure with Outer Truss Torus

2012 ◽  
Vol 588-589 ◽  
pp. 1960-1963
Author(s):  
Yun Long Yao ◽  
Guang Ying Ma ◽  
Shi Lin Dong
Keyword(s):  
Dynamic Characteristics ◽  
Lanczos Method ◽  
Load Level ◽  
Structure System ◽  
System A ◽  
Wind Vibration ◽  
String Structure ◽  
New Type ◽  
New Space ◽  
Block Lanczos Method

The large-span space beam string-structure system is a kind of economic and larger spanning spatial structure system. A new type of space beam-string-structure with outer truss torus is introduced. Sunflower-patterned space beam-string-structure was taken as an example and its dynamic characteristics under full-span load and half-span load were analyzed by block Lanczos method. The efect of prestress level and load level on dynamic behavior of the structure was studied. The results are valuable for the dynamic response research on the earthquakes and wind vibration and will provide a reference for a further design and project application of such structure.

scholarly journals Influence of loading level on the bearing capacity of RC columns strengthened by jacketing

2018 ◽  
Vol 230 ◽  
pp. 02013 ◽  
Author(s):  
Pavlo Krainskyi ◽  
Yaroslav Blikharskyy ◽  
Roman Khmil ◽  
Pavlo Vegera
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Limit State ◽  
Real Life ◽  
Load Level ◽  
Reinforced Concrete Structure ◽  
Multistory Buildings ◽  
Loading Level ◽  
Industrial Buildings ◽  
Service Load

Compressed reinforced concrete elements are quite common in construction. An example of such elements is the columns of industrial buildings, which are loaded with eccentric force, for example, from a bridge crane, columns of multistory buildings, structures subjected to compression and bending. When the reinforced concrete structure becomes unfit to future operation, it is often more economical and easy to retrofit it than to change it for a new one. Most of these structures are influenced by certain loads and unloading the structures before strengthening is not always possible. Therefore, in this work reinforced concrete structures strengthened by jacketing are investigated. To simulate the real life conditions, the loading level of 65-70% of the not strengthened column bearing capacity was maintained during jacketing. This load level simulates the actual service load on the structure. The bearing capacity load and serviceability limit state of not strengthened and jacketed reinforced concrete columns were investigated and the experimental results are presented in this paper.

Structural Integrity Assessment of Precast Concrete Slabs Employing Conventional and Recycled Coarse Aggregates via Vibration Tests

2014 ◽  
Vol 600 ◽  
pp. 504-513 ◽  
Author(s):  
Roberto Leal Pimentel ◽  
Sandro Marden Torres ◽  
Enildo Tales Ferreira ◽  
Aluísio Braz de Melo
Keyword(s):  
Structural Integrity ◽  
Load Capacity ◽  
Precast Concrete ◽  
Damping Ratio ◽  
Limit State ◽  
Load Level ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Impact Excitation ◽  
Integrity Assessment

Precast slabs were tested, consisting of ceramic blocks supported by concrete ribs and with a concrete topping a few centimeters thick. These structures are very common in Brazil, being employed for the construction of houses and small buildings. In one of the tested slabs, recycled coarse aggregate was employed while conventional aggregate (granite gravels and quartz sand) was employed in the other tested slab. This study is part of a broader experimental programme which was designed to assess the applicability of concrete containing recycled aggregates as conventional aggregate replacement. In order to get insight into the structural behavior of slabs with recycled aggregates, the main focus of this paper is to assess the effect of structural load level on vibration parameters (Resonance Frequency, Damping Ratio and Transit Time). Full scale slab structural integrity was assessed by following changes in these parameters via a vibration (modal) test employing impact excitation. The structures were tested for several static load ratios (load to ultimate loading ratios (55%, 82% and 98%)). Visual inspection of induced cracking was also performed. The results obtained indicate a reduction of stiffness in both slabs up to 50% of the stiffness of the respective uncracked structure, which followed a similar trend despite the aggregate types. As for the damping ratios, the recycled aggregate containing slab showed lower values in comparison to the control slab with conventional aggregate. Whereas the former results might indicate similar load capacity, the latter, in principle, may have implications for the vibration serviceability limit state of structures. However, although structures with lower damping ratio can potentially present vibration problems, these studied elements are not often subjected to excessive vibration in its service life.

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