EFFECT OF CONCRETE CREEP ON THE SHORTENING OF VERTICAL ELEMENTS IN HIGH-RISE BUILDINGS

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Sandy Chaaban ◽  
Ousama Baalbaki ◽  
Yehya Temsah
Keyword(s):  
Axial Stiffness ◽  
Structural Elements ◽  
Structural Members ◽  
Construction Time ◽  
Concrete Creep ◽  
High Rise ◽  
Dependent Behavior ◽  
The Difference ◽  
Analytical Behavior

Vertical structural elements are commonly subjected to the time-dependent behavior effects caused by creep which causes shortening in these elements in the direction of the load being applied. Significant amount of creep takes place instantaneously with loading and carries on for the long-term dimensions. In high-rise buildings, the axial shortening in columns is inevitable, so it cannot be ignored. The shortening is differential between vertical structural members due to the difference in axial stiffness and load distribution areas on these elements. Conventional structural analysis assumes that all structural loads are instantaneously applied to the entire completed structure. The construction sequence and loading sequence may be different depending on the construction plan. Therefore, the actual structural behavior can be significantly different from the conventional analytical behavior based on the above assumption. The objective of this study is to highlight the effect of concrete creep behavior on the shortening of vertical elements specifically in high-rise buildings. In this study, we will be considering the ACI 209R-92 model. Based on experimental data, a procedure is developed to compute the elastic shortening due to creep. A 250 meters high-rise is studied taking into consideration the stress and modulus of elasticity depending its construction time and height.

Stress Distribution in Joints in Panel Structures

2015 ◽  
Vol 1124 ◽  
pp. 209-218
Author(s):  
Pavel Svoboda ◽  
Karl Heinz Winter
Keyword(s):  
Practical Experience ◽  
Elastic Behavior ◽  
Complex Structures ◽  
Structural Elements ◽  
Structural Members ◽  
Long Term Effects ◽  
Linear Elastic ◽  
The Past ◽  
Current Design

Reinforced and pre-stressed concrete have been used increasingly for various kinds of complex structures in the past decades. The structures assembled from panels belong into this group. The current design methods rely on linear elastic analyses based on empirically derived material laws assuming homogeneous and isotropic material. Practical experience and various investigations however have indicated that majority of structures and structural elements are in fact stressed beyond the range of linear elastic behavior. In addition, long term effects may have a significant influence on the structural behavior of this category of structures and structural members.

scholarly journals Prevention of uncontrolled progressive collapse of a high-rise brick building

2018 ◽  
Vol 143 ◽  
pp. 01006
Author(s):  
Oleg Pakhmurin
Keyword(s):  
Climatic Factors ◽  
Progressive Collapse ◽  
Operational Reliability ◽  
Structural Elements ◽  
Load Bearing ◽  
Term Operation ◽  
High Rise ◽  
Failure Diagram ◽  
Stone Walls

In recent years, there is a trend towards increasing the failure rate of buildings and structures as a result of unforeseen situations. This study is aimed at assessing the operational reliability of the structure to prevent emergencies and progressive collapse. The behavior of structures affected by various factors was analyzed. The operational condition of a building with stone walls and a rigid structural frame constructed in the middle of the 20th century was considered. By means of a detailed instrumental examination, effects of long-term operation, climatic factors and violations during construction on the serviceability of the building were analyzed. Geotechnical conditions of the site were investigated. Necessary re-calculations for load-bearing structural elements and foundations were carried out. An expected failure diagram for vertical load-bearing structures of the building is presented. Proposals for preventing progressive collapse were developed on the basis of the author's technique.

Frame - Shear Wall Structures Subjected to Vertical Deformation and the Shrinkage and Creep of Concrete Relations

2012 ◽  
Vol 166-169 ◽  
pp. 3403-3407
Author(s):  
Lin Pan ◽  
Li Wei Zhang
Keyword(s):  
Shear Wall ◽  
Wall Structure ◽  
Vertical Deformation ◽  
Concrete Creep ◽  
Analysis And Design ◽  
High Rise ◽  
Wall Structures ◽  
Internal Forces ◽  
The Difference ◽  
The Impact

Frame - shear wall structural system are widely used in high-rise buildings . During the construction period , a different pressure than due to the loads and their respective axis , resulting in the existence of vertical deformation of the difference between the components , this difference will frame - shear wall structure beams internal forces have an important impact . The existence of concrete creep and shrinkage , so that the impact of further increase . A frame - shear wall structure high-rise buildings for the analysis object , using the finite element method , and analyze the impact of contraction of the construction process of concrete creep frame - shear wall structure of the vertical deformation and internal forces , a number of recommendations for the rationalization for structural analysis and design practical , in order to service engineering

Comparative Analysis of Various Kinds Concrete Creep Prediction Models

2011 ◽  
Author(s):  
Jun-Qing Lei ◽  
Hang Xu ◽  
Li-Qun Zou
Keyword(s):  
Experimental Data ◽  
High Speed ◽  
Prediction Models ◽  
Concrete Creep ◽  
High Speed Railway ◽  
Railway Line ◽  
The Difference ◽  
Short Time ◽  
Very High

The ratio of bridges to High-speed Railway line in China is very high. The influence of concrete creep to bridge structure is very high, so it is necessary to study creep of concrete in depth. In this thesis, experimental data of four important regions in China are collected, and the curves of concrete creep are analyzed. While, by comparing the domestic and foreign curves of Concrete Creep Prediction Models, the difference between them could be found. In addition, the theory of long-term deformation of concrete obtained by short-time experiment, which is proposed by Professor Bazant is used. According to experimental data, the creep curves are fittd by regression method. Finally, the comparison between common prediction models and Bazants’ theory is carried out, it can be found that the regression value is closed to the measured value.

scholarly journals The use of nanomodified concrete in construction of high-rise buildings

2018 ◽  
Vol 33 ◽  
pp. 02065
Author(s):  
Sergei Prokhorov
Keyword(s):  
Electrical Conductivity ◽  
Structural Strength ◽  
Concrete Structures ◽  
Real Life ◽  
Design Stage ◽  
Structural Elements ◽  
Term Operation ◽  
High Rise

Construction is one of the leading economy sectors. Currently, concrete is the basis of most of the structural elements, without which it is impossible to imagine the construction of a single building or facility. Their strength, reinforcement and the period of concrete lifetime are determined at the design stage, taking into account long-term operation. However, in real life, the number of impacts that affects the structural strength is pretty high. In some cases, they are random and do not have standardized values. This is especially true in the construction and exploitation of high-rise buildings and structures. Unlike the multi-storey buildings, they experience significant loads already at the stage of erection, as they support load-lifting mechanisms, formwork systems, workers, etc. The purpose of the presented article is to develop a methodology for estimating the internal fatigue of concrete structures based on changes in their electrical conductivity.

A Problem of Long - Term Digital Preservation: Difference in Humanities and Natural Sciences

2014 ◽  
Vol 3 ◽  
pp. 183-195
Author(s):  
Elena Macevičiūtė
Keyword(s):  
Social Sciences ◽  
Digital Preservation ◽  
Dynamic Activity ◽  
Private Companies ◽  
Time Line ◽  
Digital Documents ◽  
Whole Process ◽  
The Difference ◽  
Technological Science

The article deals with the requirements and needs for long-term digital preservation in different areas of scholarly work. The concept of long-term digital preservation is introduced by comparing it to digitization and archiving concepts and defined with the emphasis on dynamic activity within a certain time line. The structure of digital preservation is presented with regard to the elements of the activity as understood in Activity Theory. The life-cycle of digitization processes forms the basis of the main processing of preserved data in preservation archival system.The author draws on the differences between humanities and social sciences on one hand and natural and technological science on the other. The empirical data characterizing the needs for digital preservation within different areas of scholarship are presented and show the difference in approaches to long-term digital preservation, as well as differences in selecting the items and implementing the projects of digital preservation. Institutions and organizations can also develop different understanding of preservation requirements for digital documents and other objects.The final part of the paper is devoted to some general problems pertaining to the longterm digital preservation with the emphasis of the responsibility for the whole process of safe-guarding the cultural and scholarly heritage for the re-use of the posterior generations. It is suggested that the longevity of the libraries in comparison with much shorter life-span of private companies strengthens the claim of memory institutions to playing the central role in the long-term digital preservation.

CSO Modelling Considering Moving Storms and Tipping Bucket Gauge Failures

2007 ◽  
Vol 2 (1) ◽  
Author(s):  
M. Hochedlinger ◽  
W. Sprung ◽  
H. Kainz ◽  
K. König
Keyword(s):  
Hydrological Models ◽  
Rain Intensity ◽  
Hydrodynamic Models ◽  
Data Intensive ◽  
Storm Flow ◽  
Cell Velocity ◽  
Combined Sewer ◽  
Moving Direction ◽  
The Difference

The simulation of combined sewer overflow volumes and loads is important for the assessment of the overflow and overflow load to the receiving water to predict the hydraulic or the pollution impact. Hydrodynamic models are very data-intensive and time-consuming for long-term quality modelling. Hence, for long-term modelling, hydrological models are used to predict the storm flow in a fast way. However, in most cases, a constant rain intensity is used as load for the simulation, but in practice even for small catchments rain occurs in rain cells, which are not constant over the whole catchment area. This paper presents the results of quality modelling considering moving storms depending on the rain cell velocity and its moving direction. Additionally, tipping bucket gauge failures and different corrections are also taken into account. The results evidence the importance of these considerations for precipitation due the effects on overflow load and show the difference up to 28% of corrected and uncorrected data and of moving rain cells instead of constant raining intensities.

scholarly journals Soil erosion by snow gliding – a first quantification attempt in a subalpine area in Switzerland

2014 ◽  
Vol 18 (9) ◽  
pp. 3763-3775 ◽  
Author(s):  
K. Meusburger ◽  
G. Leitinger ◽  
L. Mabit ◽  
M. H. Mueller ◽  
A. Walter ◽  
...  
Keyword(s):  
Land Use ◽  
Soil Erosion ◽  
Land Cover ◽  
Sediment Yield ◽  
Soil Loss ◽  
Water Erosion ◽  
Erosion Rates ◽  
The Difference ◽  
Snow Gliding

Abstract. Snow processes might be one important driver of soil erosion in Alpine grasslands and thus the unknown variable when erosion modelling is attempted. The aim of this study is to assess the importance of snow gliding as a soil erosion agent for four different land use/land cover types in a subalpine area in Switzerland. We used three different approaches to estimate soil erosion rates: sediment yield measurements in snow glide depositions, the fallout radionuclide 137Cs and modelling with the Revised Universal Soil Loss Equation (RUSLE). RUSLE permits the evaluation of soil loss by water erosion, the 137Cs method integrates soil loss due to all erosion agents involved, and the measurement of snow glide deposition sediment yield can be directly related to snow-glide-induced erosion. Further, cumulative snow glide distance was measured for the sites in the winter of 2009/2010 and modelled for the surrounding area and long-term average winter precipitation (1959–2010) with the spatial snow glide model (SSGM). Measured snow glide distance confirmed the presence of snow gliding and ranged from 2 to 189 cm, with lower values on the north-facing slopes. We observed a reduction of snow glide distance with increasing surface roughness of the vegetation, which is an important information with respect to conservation planning and expected and ongoing land use changes in the Alps. Snow glide erosion estimated from the snow glide depositions was highly variable with values ranging from 0.03 to 22.9 t ha−1 yr−1 in the winter of 2012/2013. For sites affected by snow glide deposition, a mean erosion rate of 8.4 t ha−1 yr−1 was found. The difference in long-term erosion rates determined with RUSLE and 137Cs confirms the constant influence of snow-glide-induced erosion, since a large difference (lower proportion of water erosion compared to total net erosion) was observed for sites with high snow glide rates and vice versa. Moreover, the difference between RUSLE and 137Cs erosion rates was related to the measured snow glide distance (R2 = 0.64; p < 0.005) and to the snow deposition sediment yields (R2 = 0.39; p = 0.13). The SSGM reproduced the relative difference of the measured snow glide values under different land uses and land cover types. The resulting map highlighted the relevance of snow gliding for large parts of the investigated area. Based on these results, we conclude that snow gliding appears to be a crucial and non-negligible process impacting soil erosion patterns and magnitude in subalpine areas with similar topographic and climatic conditions.

scholarly journals Malpigmentation of Common Sole (Solea solea) during Metamorphosis Is Associated with Differential Synaptic-Related Gene Expression

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2273
Author(s):  
Menelaos Kavouras ◽  
Emmanouil E. Malandrakis ◽  
Ewout Blom ◽  
Kyriaki Tsilika ◽  
Theodoros Danis ◽  
...  
Keyword(s):  
Gene Expression ◽  
Nervous System ◽  
De Novo ◽  
Close Association ◽  
Ionic Channels ◽  
Long Term Potentiation ◽  
General Term ◽  
The Difference ◽  
Common Sole

In farmed flatfish, such as common sole, color disturbances are common. Dyschromia is a general term that includes the color defects on the blind and ocular sides of the fish. The purpose was to examine the difference in gene expression between normal pigmented and juveniles who present ambicoloration. The analysis was carried out with next-generation sequencing techniques and de novo assembly of the transcriptome. Transcripts that showed significant differences (FDR < 0.05) in the expression between the two groups, were related to those of zebrafish (Danio rerio), functionally identified, and classified into categories of the gene ontology. The results revealed that ambicolorated juveniles exhibit a divergent function, mainly of the central nervous system at the synaptic level, as well as the ionic channels. The close association of chromophore cells with the growth of nerve cells and the nervous system was recorded. The pathway, glutamate binding–activation of AMPA and NMDA receptors–long-term stimulation of postsynaptic potential–LTP (long term potentiation)–plasticity of synapses, appears to be affected. In addition, the development of synapses also seems to be affected by the interaction of the LGI (leucine-rich glioma inactivated) protein family with the ADAM (a disintegrin and metalloprotease) ones.

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