Journal of the South African Institution of Civil Engineering最新文献_第5页

Load spreading in ultra-thin high-strength steel-fibre-reinforced concrete pavements 超薄高强钢纤维混凝土路面的荷载分布

IF 0.4 4区工程技术

Journal of the South African Institution of Civil Engineering Pub Date : 2021-12-31 DOI: 10.17159/2309-8775/2021/v63n4a5

M. S. Smit, E. Kearsley

{"title":"Load spreading in ultra-thin high-strength steel-fibre-reinforced concrete pavements","authors":"M. S. Smit, E. Kearsley","doi":"10.17159/2309-8775/2021/v63n4a5","DOIUrl":"https://doi.org/10.17159/2309-8775/2021/v63n4a5","url":null,"abstract":"Ultra-Thin Continuously Reinforced Concrete Pavement (UTCRCP) consists of a 50 mm thin High-Strength Steel-Fibre-Reinforced Concrete (HS-SFRC) overlay placed on existing pavements as rehabilitation or used as part of new pavements. Difficulties have been experienced with the construction of UTCRCP. Additionally, the thin HS-SFRC has superior fatigue properties, but poor load-spreading ability compared to conventional concrete pavements due to its reduced thickness. This results in high deflections when the pavement is loaded. The substructure of UTCRCP plays an important role in its performance. Cement-stabilised granular materials can be used to ensure gradual load spreading with depth, but its behaviour under flexible concrete layers is not yet well understood. In this study the effect of increasing the HS-SFRC layer thickness and the effect of incorporating cement-stabilised base layers were investigated using linear elastic finite element modelling. From stress levels calculated, it was found that C1 and C2 materials perform well underneath a 50 mm HS-SFRC layer subjected to standard axle loads of 80 kN, while C3 and C4 would deteriorate faster. Stabilised layers placed below a thin, flexible concrete layer may however crack, resulting in increased damage to supporting layers. It is recommended that the response of UTCRCP should be investigated using advanced material models for the cement-stabilised base and other substructure layers.","PeriodicalId":54762,"journal":{"name":"Journal of the South African Institution of Civil Engineering","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48416144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Flow resistance in channels with large emergent roughness elements 具有大涌现粗糙度元素的通道中的流动阻力

IF 0.4 4区工程技术

Journal of the South African Institution of Civil Engineering Pub Date : 2021-12-31 DOI: 10.17159/2309-8775/2021/v63n4a1

C. S. James

引用次数: 0

Three-dimensional contact stresses of a slick solid rubber tyre on a rigid surface 光滑实心橡胶轮胎在刚性表面上的三维接触应力

IF 0.4 4区工程技术

Journal of the South African Institution of Civil Engineering Pub Date : 2021-11-11 DOI: 10.17159/2309-8775/2021/v63n3a1

M. De Beer, Y. Van Rensburg, J. Maina

{"title":"Three-dimensional contact stresses of a slick solid rubber tyre on a rigid surface","authors":"M. De Beer, Y. Van Rensburg, J. Maina","doi":"10.17159/2309-8775/2021/v63n3a1","DOIUrl":"https://doi.org/10.17159/2309-8775/2021/v63n3a1","url":null,"abstract":"The main aim of this paper is to quantify the three-dimensional contact stresses imposed by a single slow-moving (or rolling) slick solid rubber tyre on a relatively rough contact surface, such as stiff asphalt concrete or airport concrete surfacing layers. The results indicated the tyre-contact patch of a slick solid rubber tyre to be of rectangular shape for a vertical tyre loading range between 20 kN and 100 kN. The rectangular tyre contact shape was confirmed with static paper prints, as well as an electronically measured contact patch with the stress-in-motion pad device. The study included load calibration using a mass load scale, and a stress-in-motion device. These were used with an existing full-scale accelerated pavement test device, referred to as the heavy vehicle simulator. In addition, simplistic multi-layer linear elastic modelling was used to quantify differences between stress and strain responses of two types of two relatively 'stiff' based pavements, such as an asphalt concrete base and Portland cement concrete base, on similar subbase and subgrade layers. Notable differences were obtained, which could potentially influence further detailed studies on the performance of full-scale slick solid rubber tyres on typical multi-layered pavements.","PeriodicalId":54762,"journal":{"name":"Journal of the South African Institution of Civil Engineering","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48929127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

A review of methods to account for impacts of non-stationary climate data on extreme rainfalls for design rainfall estimation in South Africa 南非设计降雨量估算中非平稳气候数据对极端降雨量影响的解释方法综述

IF 0.4 4区工程技术

Journal of the South African Institution of Civil Engineering Pub Date : 2021-11-11 DOI: 10.17159/2309-8775/2021/v63n3a5

K. A. Johnson, J. Smithers, R. Schulze

{"title":"A review of methods to account for impacts of non-stationary climate data on extreme rainfalls for design rainfall estimation in South Africa","authors":"K. A. Johnson, J. Smithers, R. Schulze","doi":"10.17159/2309-8775/2021/v63n3a5","DOIUrl":"https://doi.org/10.17159/2309-8775/2021/v63n3a5","url":null,"abstract":"Frequency analysis of extreme rainfall and flood events are used to determine design rainfalls and design floods which are needed to design hydraulic structures such as dams, spillways and culverts. Standard methods for frequency analysis of extreme events are based on the assumption of a stationary climate. However, this assumption in rainfall and flood frequency analysis is being challenged with growing evidence of climate change. As a consequence of a changing climate, the frequency and magnitude of extreme rainfall events are reported to have increased in parts of South Africa, and these and other changes in extreme rainfall occurrences are expected to continue into the future. The possible non-stationarity in climate resulting in changes in rainfall may impact on the accuracy of the estimation of extreme rainfall quantities and design rainfall estimations. This may have significant consequences for the design of new hydraulic infrastructure, as well as for the rehabilitation of existing infrastructure. Hence, methods that account for non-stationary data, such as caused by climate change, need to be developed. This may be achieved by using data from downscaled global circulation models in order to identify non-stationary climate variables which affect rainfall, and which can then be incorporated into extreme value analysis of a non-stationary data series.","PeriodicalId":54762,"journal":{"name":"Journal of the South African Institution of Civil Engineering","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41321566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

A parametric design process model for box culverts 箱涵参数化设计过程模型

IF 0.4 4区工程技术

Journal of the South African Institution of Civil Engineering Pub Date : 2021-11-11 DOI: 10.17159/2309-8775/2021/v63n3a3

N. Ngobeni, A. Marnewick, D. J. van Vuuren

{"title":"A parametric design process model for box culverts","authors":"N. Ngobeni, A. Marnewick, D. J. van Vuuren","doi":"10.17159/2309-8775/2021/v63n3a3","DOIUrl":"https://doi.org/10.17159/2309-8775/2021/v63n3a3","url":null,"abstract":"This research proposes a parametric design process model to improve the structural engineering project team performance by automating the design and three-dimensional modelling procedures of box culverts. Although standardised design procedures can reduce the design time of repetitive structures such as box culverts, the increased time and effort required for revising construction drawings negatively impacts a project's performance. A literature review was conducted to develop a theoretical process model to improve the current structural design optimisation and three-dimensional modelling procedures of box culverts. The proposed process model was validated using structured interviews with professionally registered structural engineers for appropriateness to box culverts and the potential to improve project performance. The data analysis revealed that the interviewed engineers were in favour of automating the design optimisation and three-dimensional modelling procedures of box culverts. Moreover, parametric design automation would result in improved project performance when encountering an inevitable design change. However, the user's control over the output of each process should not be discarded. This study can help readers understand the transformation of the structural design and three-dimensional modelling procedures of repetitive structures, such as box culverts, into an algorithmic form to achieve improved project performance.","PeriodicalId":54762,"journal":{"name":"Journal of the South African Institution of Civil Engineering","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49462158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Applicability of CHIRPS-based satellite rainfall estimates for South Africa 基于CHIRPS的卫星降雨量估计对南非的适用性

IF 0.4 4区工程技术

Journal of the South African Institution of Civil Engineering Pub Date : 2021-11-11 DOI: 10.17159/2309-8775/2021/v63n3a4

J. A. Du Plessis, J. K. Kibii

{"title":"Applicability of CHIRPS-based satellite rainfall estimates for South Africa","authors":"J. A. Du Plessis, J. K. Kibii","doi":"10.17159/2309-8775/2021/v63n3a4","DOIUrl":"https://doi.org/10.17159/2309-8775/2021/v63n3a4","url":null,"abstract":"Long-term rainfall data with good spatial and temporal distribution is essential for all climate-related analyses. The availability of observed rainfall data has become increasingly problematic over the years due to a limited and deteriorating rainfall station network, occasioned by limited reporting and/or quality control of rainfall and, in some cases, closure of these stations. Remotely sensed satellite-based rainfall data sets offer an alternative source of information. In this study, daily and monthly rainfall data derived from Climate Hazards Group InfraRed Precipitation (CHIRPS) is compared with observed rainfall data from 46 stations evenly distributed across South Africa. Various metrics, based on a pairwise comparison between the observed and CHIRPS data, were applied to evaluate CHIRPS performance in the estimation of daily and monthly rainfall. The results show that CHIRPS data correlate well with observed monthly rainfall data for all stations used, having an average coefficient of determination of 0.6 and bias of 0.95. This study concludes that monthly CHIRPS data corresponds well, with good precision and relatively little bias when compared to observed monthly rainfall data, and can therefore be considered for use in conjunction with observed rainfall data where no or limited data is available in South Africa for hydrological analysis.","PeriodicalId":54762,"journal":{"name":"Journal of the South African Institution of Civil Engineering","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43275432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

Reduction of local scouring at round-nosed rectangular piers using a downstream bed sill 采用下游底槽减少圆头矩形墩的局部冲刷

IF 0.4 4区工程技术

Journal of the South African Institution of Civil Engineering Pub Date : 2021-11-11 DOI: 10.17159/2309-8775/2021/v63n3a6

E. Sanadgol, M. Heidarpour, R. Mohammadpour

{"title":"Reduction of local scouring at round-nosed rectangular piers using a downstream bed sill","authors":"E. Sanadgol, M. Heidarpour, R. Mohammadpour","doi":"10.17159/2309-8775/2021/v63n3a6","DOIUrl":"https://doi.org/10.17159/2309-8775/2021/v63n3a6","url":null,"abstract":"This study investigated the effectiveness of bed sills in reducing the scour depth with time at rectangular piers in a laboratory. Experiments were conducted just below the threshold of sediment motion (U/Uc = 0.95) for round-nosed piers with the length-to-width ratios of L/b = 1, 2, 3 and 4. Accordingly, a 1 cm thick PVC section as wide as the channel was used as the bed sill, which was flush with the bed and located at various distances, D, in the downstream of the piers, i.e. D/b = 0, 1, 2 and 3. It was found that the efficiency of the bed sill for a rectangular pier was significantly less than that for the circular one; there was a decrease in efficiency and scour depth with an increase of the pier length. The maximum efficiency obtained for the round-nosed piers with L/b = 1, 2, 3 and 4 was 32.5%, 21.3%, 14.4% and 5.7%, respectively. The application of a bed sill to reduce the local scour in round-nosed rectangular piers, when the length-to-width ratio exceeds 2, is therefore not recommended. Furthermore, the efficiency of the bed sill is the best when it is attached to the downstream end of the pier; its efficiency is decreased when increasing its distance from the pier.","PeriodicalId":54762,"journal":{"name":"Journal of the South African Institution of Civil Engineering","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44461774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Static pile capacity from the rapid test via the unloading-point method 卸载点法快速测试的静态桩承载力

IF 0.4 4区工程技术

Journal of the South African Institution of Civil Engineering Pub Date : 2021-06-01 DOI: 10.17159/2309-8775/2021/v63n2a3

I. Luker

引用次数: 0

Prediction of California Bearing Ratio and compaction characteristics of Transvaal soils from indicator properties 从指标性质预测德兰士瓦土的加州承载比和压实特性

IF 0.4 4区工程技术

Journal of the South African Institution of Civil Engineering Pub Date : 2021-06-01 DOI: 10.17159/2309-8775/2021/v63n2a6

F. Haupt, F. Netterberg

引用次数: 6

South African infrastructure condition - an opinion survey for the sAICE Infrastructure Report Card 南非基础设施状况-《南非基础设施报告卡》的意见调查

IF 0.4 4区工程技术

Journal of the South African Institution of Civil Engineering Pub Date : 2021-06-01 DOI: 10.17159/2309-8775/2021/v63n2a5

F. C. Rust, K. Wall, M. Smit, S. Amod

{"title":"South African infrastructure condition - an opinion survey for the sAICE Infrastructure Report Card","authors":"F. C. Rust, K. Wall, M. Smit, S. Amod","doi":"10.17159/2309-8775/2021/v63n2a5","DOIUrl":"https://doi.org/10.17159/2309-8775/2021/v63n2a5","url":null,"abstract":"ABSTRACT The South African Institution of Civil Engineering (SAICE) Infrastructure Report Cards of 2006, 2011 and 2017 reported that much of the South African infrastructure is in a poor condition. To augment the recent 2017 Report Card, a survey was, for the first time, conducted amongst SAICE members to obtain their opinion on the condition of infrastructure (in terms of a grading), the trend of the condition over time, as well as the reasons for the individual's grading. The 669 respondents indicated that, apart from a few exceptions such as national airports and the Gautrain, much of the infrastructure is in a poor state, which is very similar to the results obtained from the SAICE Report Card process. The results were also analysed per province and indicated that, in the opinion of respondents, specific provinces in particular are struggling with poor infrastructure. The main reasons given for the poor infrastructure were a lack of maintenance, lack of institutional capability, lack of sufficient funding and over-loading of infrastructure. Keywords: infrastructure condition, SAICE Infrastructure Report Card, Infrastructure grading system","PeriodicalId":54762,"journal":{"name":"Journal of the South African Institution of Civil Engineering","volume":"20 21","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41261934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3