Time-dependent deformations of concrete columns under different construction load histories

2019 ◽  
Vol 22 (8) ◽  
pp. 1845-1854 ◽  
Author(s):  
Dujian Zou ◽  
Chengcheng Du ◽  
Tiejun Liu ◽  
Jun Teng ◽  
Hanbin Cheng
Keyword(s):  
Prediction Models ◽  
Plain Concrete ◽  
Concrete Columns ◽  
In Situ Monitoring ◽  
Time Dependent ◽  
Construction Stage ◽  
Inappropriate Use ◽  
High Rise ◽  
Multi Stage ◽  
Axial Shortening

The adverse effects caused by differential axial shortening in high-rise buildings have received increasing attention with growing building height. However, the axial shortening analysis still lacks accuracy compared to the in-situ monitoring results of practical high-rise buildings during construction stage. It is imperative to identify the error sources, and the applicability of the current shortening prediction models should be test verified. In this study, 14 plain concrete columns were cast, and the multi-stage load method was applied to approximately simulate the loading history of axial concrete members during construction stage. The time-dependent deformations of loaded concrete specimens were measured, and a comparative analysis was conducted between test results and numerical prediction values. It is found that the measured deformations of multi-stage loading cases are all underestimated compared with predicted results, and this underestimation may be mainly caused by the inappropriate use of elastic modulus. It further indicates that the axial shortening analysis of high-rise buildings tends to underestimate the actual shortening value when the traditional calculation method is used. This study provides a reference for explaining the mismatch between the analytical results and the actual shortening values.

Infrastructure Sustainability

2011 ◽  
pp. 202-211
Author(s):  
Praveen Moragaspitiya ◽  
David Thambiratnam ◽  
Nimal Perera ◽  
Tommy Chan
Keyword(s):  
Numerical Procedure ◽  
Time Dependent ◽  
Test Procedures ◽  
High Rise ◽  
Secondary Systems ◽  
Content Variable ◽  
True Time ◽  
And Performance ◽  
Concrete Elements ◽  
Axial Shortening

High density development has been seen as a contribution to sustainable development. However, a number of engineering issues play a crucial role in the sustainable construction of high rise buildings. Non linear deformation of concrete has an adverse impact on high-rise buildings with complex geometries, due to differential axial shortening. These adverse effects are caused by time dependent behaviour resulting in volume change known as ‘shrinkage’, ‘creep’ and ‘elastic’ deformation. These three phenomena govern the behaviour and performance of all concrete elements, during and after construction. Reinforcement content, variable concrete modulus, volume to surface area ratio of the elements, environmental conditions, and construction quality and sequence influence on the performance of concrete elements and differential axial shortening will occur in all structural systems. Its detrimental effects escalate with increasing height and non vertical load paths resulting from geometric complexity. The magnitude of these effects has a significant impact on building envelopes, building services, secondary systems, and lifetime serviceability and performance. Analytical and test procedures available to quantify the magnitude of these effects are limited to a very few parameters and are not adequately rigorous to capture the complexity of true time dependent material response. With this in mind, a research project has been undertaken to develop an accurate numerical procedure to quantify the differential axial shortening of structural elements. The procedure has been successfully applied to quantify the differential axial shortening of a high rise building, and the important capabilities available in the procedure have been discussed. A new practical concept, based on the variation of vibration characteristic of structure during and after construction and used to quantify the axial shortening and assess the performance of structure, is presented.

Prediction Models of Shrinkage and Creep for Concrete Columns

2011 ◽  
Vol 243-249 ◽  
pp. 1583-1588
Author(s):  
Yi Gang Lv ◽  
Jian Ren Zhang ◽  
Kang Xu
Keyword(s):  
Prediction Models ◽  
Plain Concrete ◽  
Least Square Method ◽  
Concrete Columns ◽  
Shrinkage Strain ◽  
Least Square ◽  
Creep Effect ◽  
Shrinkage And Creep ◽  
Term Performance

In constant temperature and humidity environment, the properties of shrinkage and creep for a group of plain concrete and reinforced concrete columns were observed in long-term and experimental method. The curves of concrete shrinkage and creep effect with time were obtained. Checking coefficient and type coefficient of shrinkage and creep effect were put forward in order to predict models of shrinkage and creep. Using the least square method, functions of checking coefficient and type coefficient were acquired and the prediction models of shrinkage strain and creep coefficient of concrete were obtained based on the modification of the formula of JTG D62-2004. The foundation is laid for the application of the long-term performance research in bridge structure.

PERILAKU RANGKAK SUSUT TERHADAP LENDUTAN STRUKTUR JEMBATAN BENTANG PANJANG

2017 ◽  
Vol 13 (4) ◽  
pp. 260 ◽  
Author(s):  
Baskoro Abdi Praja ◽  
Andreas Triwiyono
Keyword(s):  
Time Dependent ◽  
Construction Stage ◽  
Stage Analysis

Jembatan Lemah Ireng 1 pada ruas jalan Tol Semarang-Bawen terbuat dari beton prategang dengan panjang total 879 m. Pada masa konstruksi dua perbedaan kondisi teknik terhadap rencana, yakni perubahan material pasir dan perubahan perpindahan traveler. Keduanya diduga sebagai penyebab perbedaan elevasi desain dengan elevasi aktual sehingga dilakukan levelling aspal dengan tebal bervariasi. Jembatan ini didesain untuk memenuhi masa layan 100 tahun namun berdasarkan kondisi aktual, diperlukan peninjauan terhadap perilaku dan kuat layan jembatan hingga umur rencana. Dengan pengaruh variasi pembebanan jangka panjang (rangkak susut) dan kondisi perubahan teknis akibat penambahan aspal, penelitian rangkak susut ini perlu dilakukan untuk mengetahui perilaku lendutan pada gelagar boks jembatan hingga umur rencana. Beberapa tahapan pembebanan yang dilakukan adalah menerapkan beban levelling aspal, dan beban rangkak dan susut dengan menggunakan variasi durasi jangka panjang dengan interval 5, 10 , 15, 20, 40, 60, 80 dan 100 tahun. Analisis dilakukan secara linear statik serta memanfaatkan fasilitas Construction Stage Analysis untuk efek time-dependent pada software Midas Civil 2011. Penelitian ini dilakukan dengan hanya meninjau aksi tetap. Perilaku rangkak susut jembatan cukup signifikan di 5 tahun pertama setelah konstruksi selesai. Lendutan maksimum rangkak susut dan total berada di bentang terpanjang (P4-P5)  masing-masing sebesar 17,53 dan 25,71 cm. Lendutan yang terjadi hingga umur rencana 100 tahun masih dalam batas izin, namun tetap perlu pengawasan yang terencana. Dampak minimum rangkak susut terhadap total lendutan pada jembatan Lemah Ireng 1 sebesar 45%. Hal ini menunjukkan rangkak susut terhadap defleksi total hingga umur rencana merupakan efek jangka panjang yang relatif besar.

Local Calibration of Pavement Mechanistic-Empirical Faulting Reliability using Pavement Management Data

2021 ◽  
pp. 036119812110013
Author(s):  
Lucio Salles de Salles ◽  
Lev Khazanovich
Keyword(s):  
Model Calibration ◽  
Prediction Models ◽  
Plain Concrete ◽  
Performance Model ◽  
Pavement Management ◽  
Pavement Design ◽  
Reliability Model ◽  
Transverse Joint ◽  
Design Characteristics ◽  
And Performance

The Pavement ME transverse joint faulting model incorporates mechanistic theories that predict development of joint faulting in jointed plain concrete pavements (JPCP). The model is calibrated using the Long-Term Pavement Performance database. However, the Mechanistic-Empirical Pavement Design Guide (MEPDG) encourages transportation agencies, such as state departments of transportation, to perform local calibrations of the faulting model included in Pavement ME. Model calibration is a complicated and effort-intensive process that requires high-quality pavement design and performance data. Pavement management data—which is collected regularly and in large amounts—may present higher variability than is desired for faulting performance model calibration. The MEPDG performance prediction models predict pavement distresses with 50% reliability. JPCP are usually designed for high levels of faulting reliability to reduce likelihood of excessive faulting. For design, improving the faulting reliability model is as important as improving the faulting prediction model. This paper proposes a calibration of the Pavement ME reliability model using pavement management system (PMS) data. It illustrates the proposed approach using PMS data from Pennsylvania Department of Transportation. Results show an increase in accuracy for faulting predictions using the new reliability model with various design characteristics. Moreover, the new reliability model allows design of JPCP considering higher levels of traffic because of the less conservative predictions.

A comparative study on the differential axial shortening in high‐rise buildings

2021 ◽  
Author(s):  
Rafael Ruiz ◽  
Leonardo Todisco ◽  
Alfredo Pazos ◽  
Hugo Corres
Keyword(s):  
Comparative Study ◽  
High Rise ◽  
Axial Shortening

Mechanical Properties of Large Scale Confined Concrete

2011 ◽  
Vol 94-96 ◽  
pp. 1983-1988
Author(s):  
Jia Song ◽  
Zhen Bao Li ◽  
Yong Ping Xie ◽  
Xiu Li Du ◽  
Yue Gao
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Axial Compression ◽  
Large Scale ◽  
Plain Concrete ◽  
Concrete Columns ◽  
Confined Concrete ◽  
Transverse Reinforcement ◽  
Test Results ◽  
Reinforcement Configuration

An experimental study was made of the mechanical properties of large scale confined concrete subjected to the axial compression test. Eleven tied concrete columns and six plain concrete prisms were tested. In the test, each specimen had the same transverse reinforcement configuration, and similar volumetric ratio of lateral steel, while different size. The test results in this paper indicate that the size of the specimen has no obvious relationship with the ultimate strength, however, it does affect the post-peak ductility to some extent. As a supplement to the experimental study, a finite element method was adopted to imitate the mechanical behavior of the confined concrete under axial compression. The results of the imitation in this paper indicate the confinement mechanism of large scale specimens.

Causes and Control Measures of Mass Concrete Crack of High-Rise Building Basement Foundation Slab

2010 ◽  
Vol 163-167 ◽  
pp. 1609-1613 ◽  
Author(s):  
Hui Hong Feng ◽  
Xi Wang
Keyword(s):  
Control Measures ◽  
Mass Concrete ◽  
Construction Process ◽  
Construction Stage ◽  
Foundation Slab ◽  
High Rise ◽  
High Rise Building ◽  
Concrete Crack ◽  
And Control

This paper discusses that the causes and the corresponding control measures of mass concrete crack in the construction stage. And through the analysis of engineering example, it describes the application of the control measures of mass concrete crack in the basement foundation slab of high-rise building in construction process, and analyses the construction effect of its.

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