Civil Engineering Design最新文献_第5页

Volumetric intersections: Modularization approaches for freeform prefab concrete construction 体积交叉点:自由形式预制混凝土结构的模块化方法

Civil Engineering Design Pub Date : 2022-03-03 DOI: 10.1002/cend.202100047

David Stieler, Tobias Schwinn, Achim Menges

引用次数: 1

Monitoring the microstructural deterioration of concrete exposed to leaching in purified water 纯净水浸出混凝土微观结构劣化的监测

Civil Engineering Design Pub Date : 2021-12-15 DOI: 10.1002/cend.202100051

Robert Schulte Holthausen, Melanie Merkel, Wolfgang Breit, Michael Raupach

{"title":"Monitoring the microstructural deterioration of concrete exposed to leaching in purified water","authors":"Robert Schulte Holthausen, Melanie Merkel, Wolfgang Breit, Michael Raupach","doi":"10.1002/cend.202100051","DOIUrl":"10.1002/cend.202100051","url":null,"abstract":"Concrete is considered to be durable in permanent contact with water, making it a preferred material for the construction of drinking water reservoirs. More severe conditions, however, such as contact with purified water lead to the leaching of calcium and the deterioration of concrete surfaces. Due to the diffusive nature, deterioration begins superficially and ingresses with time. Consequently, concrete surfaces are severely damaged and the rebar-protective alkalinity can be lost. In this study, results from long-term laboratory leaching experiments in purified water of differently prepared concrete surfaces relevant for drinking water reservoirs are reported. Samples are monitored by both conventional laboratory techniques and, for the first time, by single-sided 1H nuclear magnetic resonance to gain knowledge on appearance and performance as well as the microstructural changes with sub-millimeter depth resolution. Results give a deepened insight into the time- and depth-depending material changes. Concrete with a lower w/c ratio, more durable cement, or a densified surface shows a slowed deterioration. The progressing leaching deterioration is described using a combined diffusion-erosion model that allows a more direct comparison of results to other exposures.","PeriodicalId":100248,"journal":{"name":"Civil Engineering Design","volume":"4 4","pages":"99-109"},"PeriodicalIF":0.0,"publicationDate":"2021-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85873302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Crack width verification and minimum reinforcement according to EC 2: Current model with specifications in Germany and Austria vs proposal for revision 根据EC 2的裂缝宽度验证和最小加固:德国和奥地利规范的当前模型与修订建议

Civil Engineering Design Pub Date : 2021-12-15 DOI: 10.1002/cend.202100045

Nguyen Viet Tue, Ekkehard Fehling, Dirk Schlicke, Christina Krenn

{"title":"Crack width verification and minimum reinforcement according to EC 2: Current model with specifications in Germany and Austria vs proposal for revision","authors":"Nguyen Viet Tue, Ekkehard Fehling, Dirk Schlicke, Christina Krenn","doi":"10.1002/cend.202100045","DOIUrl":"10.1002/cend.202100045","url":null,"abstract":"Limiting crack widths to an acceptable level and determining the required minimum reinforcement are important tasks in the design of reinforced and prestressed concrete structures. Experience with different types of structures, ranging from watertight concrete structures to prestressed concrete bridges, shows that the concept currently applied in Germany and Austria is very effective and that significant changes are not necessary. The current draft for the revision of the EC2 (prEC2), however, presents a new concept for crack width verification and minimum reinforcement. In contrast to the concept currently used in Germany and Austria, this new concept is based more on the analysis and good reproduction of observations made in laboratory experiments and takes less account of the mechanical relationships of reinforced or prestressed concrete after cracking. For this purpose, numerous empirical factors are introduced which not only complicate the understanding but also the application in practice. However, an improvement in the accuracy of the crack width prediction is not achieved and the minimum reinforcement is significantly underestimated, especially for prestressed cross sections and thick members. In this article, the new concept set out in prEC2 is explained in detail. Its main weaknesses and contradictions are discussed by a comparison with the concept currently applied in Germany and Austria as well as detailed analysis of 2D FEM simulations with discrete cracks and adequate regard of the bond stress-slip relationship at the reinforcement-concrete interface. This should provide the basis for a factual discussion before the introduction of prEC2 into practice.","PeriodicalId":100248,"journal":{"name":"Civil Engineering Design","volume":"3 5-6","pages":"210-228"},"PeriodicalIF":0.0,"publicationDate":"2021-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cend.202100045","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86366536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Influences on the structural response of beams in drop tower experiments 落塔试验对梁结构响应的影响

Civil Engineering Design Pub Date : 2021-11-03 DOI: 10.1002/cend.202100040

Lena Leicht, Birgit Beckmann, Manfred Curbach

引用次数: 2

Experimental and numerical determination of the screw deformation in laminated beech veneer lumber as a result of moisture-induced swelling 湿胀引起的山毛榉胶合板螺旋变形的实验和数值测定

Civil Engineering Design Pub Date : 2021-10-31 DOI: 10.1002/cend.202100016

Daniela Gerstorfer, Thomas Forte, Josef Füssl

{"title":"Experimental and numerical determination of the screw deformation in laminated beech veneer lumber as a result of moisture-induced swelling","authors":"Daniela Gerstorfer, Thomas Forte, Josef Füssl","doi":"10.1002/cend.202100016","DOIUrl":"10.1002/cend.202100016","url":null,"abstract":"The strong hygroscopic behavior of wood can lead to severe moisture-induced swelling deformations, especially perpendicular to the grain direction. Fully threaded screws arranged in this direction can be used as reinforcement and to constrain those deformations. Depending on the wood moisture content increase, tensile stresses in the screws and compression stresses in the surrounding solid wood evolve. A sufficiently accurate prediction of the maximum stresses occurring is important for reliable structural designs. For this reason, moisture-induced swelling experiments for two different configurations of screw diameter and specimen dimensions were performed within this work. Due to its homogeneity and its high swelling rate perpendicular to the grain, beech laminated veneer lumber (LVL) was used. A moisture content increase from oven-dry to about 7% led to screw tensile stresses in the magnitude of the yield strength and to highly nonlinear effects in the surrounding wood material. By means of a two-dimensional finite-element-based numerical simulation model, taking into account orthotropic plasticity and moisture-dependent material properties, the experiments could be simulated with high accuracy. The numerical results agree well with experimental observations. Based on a small parameter study, new insights into the complex interaction behavior between beech LVL and fully threaded screws could be gained.","PeriodicalId":100248,"journal":{"name":"Civil Engineering Design","volume":"3 5-6","pages":"171-178"},"PeriodicalIF":0.0,"publicationDate":"2021-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81763300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An innovative resource-efficient timber-concrete-composite ceiling system: Feasibility and environmental performance 一种创新的资源高效的木材-混凝土复合天花板系统:可行性和环保性能

Civil Engineering Design Pub Date : 2021-10-19 DOI: 10.1002/cend.202100022

Benjamin Kromoser, Philipp Holzhaider

引用次数: 1

Lifetime predictions of prestressed concrete bridges—Evaluating parameters of relevance using Sobol' indices 预应力混凝土桥梁寿命预测——使用Sobol指数评估相关参数

Civil Engineering Design Pub Date : 2021-09-27 DOI: 10.1002/cend.202100009

David Sanio, Mark Alexander Ahrens, Peter Mark

{"title":"Lifetime predictions of prestressed concrete bridges—Evaluating parameters of relevance using Sobol' indices","authors":"David Sanio, Mark Alexander Ahrens, Peter Mark","doi":"10.1002/cend.202100009","DOIUrl":"10.1002/cend.202100009","url":null,"abstract":"The residual structural lifetime of concrete bridges is often limited by fatigue of the prestressing steel. In practice, numerical calculations of the structure are combined with Miner's rule—based on load frequencies and stress amplitudes—to estimate the damage. Thereby, various parameters must be accounted for whereof a few are actually relevant. Structural monitoring is valuable to increase the accuracy of lifetime predictions, but usually experts choose the right parameters on experience only. A more objective assessment can be reached by sensitivity analysis. A powerful method is provided by Sobol's variance-based indices. They quantify the influence of a single parameter's variance on the model's total variance and account for interactions in nonlinear models, too. Exemplified on a reference structure, sensitivity indices are determined. Meanwhile specific characteristics like the nonlinear behavior of concrete after cracking are considered. In this case, the key elements of lifetime prediction turn out to be the time-dependent losses of prestress and the traffic loads.","PeriodicalId":100248,"journal":{"name":"Civil Engineering Design","volume":"4 5-6","pages":"143-153"},"PeriodicalIF":0.0,"publicationDate":"2021-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cend.202100009","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77775886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Heating rate with regard to temperature release of UHPC under cyclic compressive loading 循环压缩加载下UHPC温度释放的升温速率

Civil Engineering Design Pub Date : 2021-08-27 DOI: 10.1002/cend.202100020

M. Deutscher, S. Scheerer

引用次数: 1

Investigating the feasibility of using carbon fiber tapes as reinforcement for 3D concrete printing 研究碳纤维带作为混凝土3D打印增强材料的可行性

Civil Engineering Design Pub Date : 2021-08-05 DOI: 10.1002/cend.202100024

Martin Scheurer, Philipp Quenzel, Peter Nölke, Jonas Reuter‐Schniete, T. Gries

引用次数: 3

Integrative computational design and construction: Rethinking architecture digitally 综合计算设计与建造:对建筑的数字化反思

Civil Engineering Design Pub Date : 2021-06-22 DOI: 10.1002/CEND.202100027

J. Knippers, Cordula Kropp, A. Menges, O. Sawodny, D. Weiskopf

{"title":"Integrative computational design and construction: Rethinking architecture digitally","authors":"J. Knippers, Cordula Kropp, A. Menges, O. Sawodny, D. Weiskopf","doi":"10.1002/CEND.202100027","DOIUrl":"https://doi.org/10.1002/CEND.202100027","url":null,"abstract":"Increasing the construction capacity, while at the same time significantly reducing harmful emissions and consumption of nonrenewable resources, and still providing a liveable and affordable built environment, provides a great challenge for future construction. In order to achieve this, both the productivity of construction processes and the energy and resource efficiency of construction systems have to be improved in a reciprocal process. Digital technologies make it possible to address these challenges in novel ways. The vision of this Cluster of Excellence IntCDC at the University of Stuttgart and the Max Planck Institute for Intelligent Systems is to harness the full potential of digital technologies to rethink design and construction based on integration and interdisciplinarity, with the goal of laying the methodological foundations to profoundly modernize the design and construction process and related building systems by adopting a systematic, holistic and integrative computational approach. One key objective is to develop an overarching methodology of “ co-designing ” methods, processes and systems based on interdisciplinary research encompassing architecture, structural engineering, building physics, engineering geodesy, manufacturing and systems engineering, computer science and robotics, and humanities and social sciences. In this way, the Cluster aims to address the ecological, economic and social challenges and to provide the prerequisites for a high-quality and sustainable built environment and a digital building culture. for building in the future is to build more, while emitting fewer pollutants and using fewer nonrenewable resources, and still create a high-quality and liveable built environment. In a mutually influencing process, both the productivity of the building process and the energy and resource efficiency of the building systems must be improved. Digital technologies offer new approaches to solving these challenges. The and","PeriodicalId":100248,"journal":{"name":"Civil Engineering Design","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78420601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 24