scholarly journals The Rehabilitation of Structures on the National Route 10 Section 12 between Upington Km 0.0 and Nakop Km134.17

2018 ◽  
Vol 199 ◽  
pp. 10003
Author(s):  
Tiago Massingue ◽  
Bennie Zietsman
Keyword(s):  
South Africa ◽  
Compressive Strength ◽  
Bridge Management ◽  
Bridge Management System ◽  
Existing Structures ◽  
Floor Slabs ◽  
Deck Slabs ◽  
Northern Cape ◽  
Materials Used

National Route 10 Section 12 is situated between Upington and Nakop at the border between South Africa and Namibia in the Northern Cape Province. As part of SANRAL’s Bridge Management System, three bridges and twenty four major in-situ cast culverts were identified to be in need of rehabilitation and/or strengthening. This paper details the condition of the existing structures as well as the methods and materials used to repair and strengthen the structures to be in a safe and serviceable condition. Due to the harsh environmental conditions, as well as the remoteness of the structures, the methods and materials for repair had to be carefully considered. In this regard, special reference is made to the use of carbon fibre strips to increase the bearing capacity of the bridgeand culvert deck slabs. The method for the strengthening of the floor slabs and internal walls of a number of culverts, for which the compressive strength of the existing concrete was found to be in the order of 1.0 MPa, is also discussed.

Assessment of the Concrete Compressive Strength in Existing Structures Based on Core Test Results

2018 ◽  
Vol 272 ◽  
pp. 238-243 ◽  
Author(s):  
Viktar V. Tur ◽  
Stanislav S. Derechennik
Keyword(s):  
Monte Carlo Simulation ◽  
Quality Control ◽  
Compressive Strength ◽  
Structural Reliability ◽  
Reliability Estimation ◽  
Control Procedure ◽  
Test Results ◽  
Concrete Compressive Strength ◽  
Existing Structures

Evaluation of the concrete compressive strength in existing structures is an important problem, which is associated with structural reliability estimation as well as a quality control procedure. In accordance with a new concept of EN 13791, reported by T.A.Harrison, one of the main targets of the standard is to determine not a class, but in-situ characteristic concrete compressive strength. Hereby proposed criterion for the estimation of the in-situ characteristic concrete compressive strength is based on the non-parametric confidence interval for quantile. This criterion was verified by the both Monte Carlo simulation and test results under the real concrete structures.

scholarly journals Microstratigraphic evidence of in situ fire in the Acheulean strata of Wonderwerk Cave, Northern Cape province, South Africa

2012 ◽  
Vol 109 (20) ◽  
pp. E1215-E1220 ◽  
Author(s):  
F. Berna ◽  
P. Goldberg ◽  
L. K. Horwitz ◽  
J. Brink ◽  
S. Holt ◽  
...  
Keyword(s):  
South Africa ◽  
Northern Cape

scholarly journals Adapting Artificial Intelligence to Improve In Situ Concrete Compressive Strength Estimations in Rebound Hammer Tests

2020 ◽  
Vol 7 ◽  
Author(s):  
Yu Ren Wang ◽  
Yen Ling Lu ◽  
Dai Lun Chiang
Keyword(s):  
Artificial Intelligence ◽  
Compressive Strength ◽  
Prediction Models ◽  
Concrete Compressive Strength ◽  
Concrete Material ◽  
Rebound Hammer ◽  
Existing Structures ◽  
Core Samples ◽  
Using Data

Compressive strength is probably one the most crucial properties of concrete material. For existing structures, core samples are drilled and tested to obtain the concrete compressive strength. Many times, taking core samples is not feasible, and as a result, nondestructive methods to examine the concrete are required. The rebound hammer test is one of the most popular methods to estimate concrete compressive strength without causing damage to the existing structure. The test is inexpensive and can be easily conducted compared to other nondestructive testing methods. Also, concrete compressive strength estimations can be obtained almost instantly. However, previous results have shown that concrete compressive strength estimations obtained from rebound hammer tests are not very accurate. As a result, this research attempts to apply artificial intelligence prediction models to estimate concrete compressive strength using data from in situ rebound hammer tests. The results show that artificial intelligence methods can effectively improve in situ concrete compressive strength estimations in rebound hammer tests.

scholarly journals In Situ Compression Stress-Deformation Measurements along the Timber Depth Profile

2013 ◽  
Vol 778 ◽  
pp. 209-216 ◽  
Author(s):  
Miloš Drdácký ◽  
Michal Kloiber
Keyword(s):  
Compressive Strength ◽  
Small Diameter ◽  
Direct Determination ◽  
New Device ◽  
Existing Structures ◽  
Stress Deformation ◽  
Modulus Of Deformation ◽  
Novel Concept

The paper presents a novel concept and a prototype of a diagnostic tool for in-situ assessment of timber in existing structures and buildings. The device enables direct determination of conventional compressive strength and modulus of deformation in arbitrary depth along timber profile. The measurement of the stress-deformation relationship is performed in a prepared hole of a very small diameter by means of a special small size symmetrical loading jack. Testing and verification of the new device behaviour during loading of wood along the fibres has been carried out on fir which is the most frequent wood species in European buildings. The comparison of stress-strain diagrams acquired by means of the new device with those measured in compliance with the European standard for testing of wood shows a very good correlation including the determination of the compressive strength values. This semi-destructive method causes a very gentle damage and can be also used for the assessment of historic timber structures.

Strength evaluation of an existing concrete bridge based on core and non-destructive test data

1987 ◽  
Vol 14 (2) ◽  
pp. 145-154 ◽  
Author(s):  
Andrew Scanlon ◽  
Leonid Mikhailovsky
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Nondestructive Testing ◽  
Probabilistic Approach ◽  
Pulse Velocity ◽  
Design Parameters ◽  
Concrete Bridge ◽  
Strength Evaluation ◽  
Existing Structures

The use of concrete cores and nondestructive testing for strength evaluation of existing structures is illustrated through an evaluation of an existing concrete bridge. The results confirm that rebound hammer number should not be used alone as an indicator of in situ compressive strength. Reasonably good correlation is demonstrated between pulse velocity and compressive strength, with a slight improvement when pulse velocity and rebound number are combined.A probabilistic approach to structural evaluation of existing structures is proposed in which the variability of in situ concrete compression strength and uncertainty associated with indirect nondestructive testing are incorporated. An example of shear strength evaluation is given, which indicates a range of increase in shear strength compared with initial design parameters of 17–37% depending on the amount and type of data available.

scholarly journals Hardness, compressive strength and resilience of complete denture lining materials: an in situ study

2020 ◽  
Vol 68 ◽  
Author(s):  
Hugo de CARVALHO JUNIOR ◽  
Vítor Hugo Marçal de CARVALHO ◽  
Roberta Tarkany BASTING
Keyword(s):  
Compressive Strength ◽  
Acrylic Resin ◽  
Time Intervals ◽  
Soft Liner ◽  
Term Evaluation ◽  
Materials Used ◽  
Tissue Conditioner ◽  
Hardness Values

ABSTRACT Objective The aim of this study was to evaluate the in situ hardness, compressive strength and resilience of soft lining materials used in total removable prostheses in different time intervals Methods total of 48 rectangular test specimens (10 x 3 x 2 mm) were fabricated of each of the polyvinylsiloxane-based soft liner (Mucopren Soft) and acrylic resin-based material (Trusoft), which were placed on total removable prostheses bases of 12 volunteers (n = 12). The hardness (Shore A), compressive strength (in MPa) and resilience (in Kgf/cm2) were evaluated in different time intervals: 0, 7, 30 and 60 days, at three different locations of the specimens surface. Results The two-way ANOVA and Tukey test showed that the polyvinylsiloxane-based soft liner presented higher hardness values (p = 0.0113) and higher compressive strength (p=0.0252) than the acrylic resin-based material at immediate and 7 days evaluations. The polyvinylsiloxane-based soft liner presented higher resilience values than the acrylic resin-based material at all times (p = 0.0133). Hardness and compressive strength were similar for both materials at 30 and 60 days evaluations. Conclusions For both materials,there was a tendency for an increase of hardness, compressive strength and resilience over time, influenced by the composition of the tissue conditioner. The polyvinylsiloxane-based soft liner presented higher hardness, compressive strength and resilience than the acrylic resin-based material, specially considering a long-term evaluation up to 60 days.

scholarly journals Case Study in The Northern Cape (Loopeng Area), South Africa, Confirming Occurrence of a Collapsible Soil Structure in Transported Soils

2021 ◽  
Author(s):  
Frederik Daniël Jacobus Stapelberg
Keyword(s):  
South Africa ◽  
Soil Profile ◽  
Soil Structure ◽  
Soil Conditions ◽  
Collapsible Soil ◽  
Local Conditions ◽  
Geotechnical Characteristics ◽  
Structure Description ◽  
Northern Cape

Abstract Testing was performed on transported soils belonging to recently deposited sandy-silty soil deposits occurring in the Northern Cape Province, South Africa in order to determine the occurrence and order of magnitude of a collapsing sand soil structure. Various empirical geotechnical characteristics including: in situ soil profile structure description, particle grading curve and clay content, soil classification, soil density and void ratio were compared to collapse potential values determined with oedometer testing in order to judge the success with which the empirical characteristics can be utilized to predict the occurrence of a collapsible soil structure.From the results it is clear that a collapsing sand structure exists in the transported soils and the empirical descriptors mostly correctly indicate the occurrence or the particular soil structure when compared to previous studies on collapsing sands. The one descriptor which reflects a relatively poor correction between the descriptor and the soil structure (in situ soil profile structure description) is considered to be a poor indicator of the collapsible soil structure due to erroneous or poor in situ soil structure observations resulting from unfavourable local conditions namely dry, dusty soil conditions and very brief intact standup time of test pit side walls.

OPERATIONAL STATE OF BRIDGES OF UKRAINE

2019 ◽  
pp. 57-68
Author(s):  
Larysa Bodnar ◽  
Petro Koval ◽  
Sergii Stepanov ◽  
Liudmyla Panibratets
Keyword(s):  
Management System ◽  
The State ◽  
Operating Conditions ◽  
Bridge Management ◽  
Bridge Management System ◽  
Program Complex ◽  
Operating Condition ◽  
Software Complex ◽  
Automatic Mode ◽  
The Status

A significant part of Ukrainian bridges on public roads is operated for more than 30 years (94 %). At the same time, the traffic volume and the weight of vehicles has increased significantly. Insufficient level of bridges maintenance funding leads to the deterioration of their technical state. The ways to ensure reliable and safe operation of bridges are considered. The procedure for determining the predicted operational status of the elements and the bridge in general, which has a scientific novelty, is proposed. In the software complex, Analytical Expert Bridges Management System (AESUM), is a function that allows tracking the changes in the operational status of bridges both in Ukraine and in each region separately. The given algorithm of the procedure for determining the predicted state of the bridge using a degradation model is described using the Nassie-Schneidermann diagram. The model of the degradation of the bridge performance which is adopted in Ukraine as a normative one, and the algorithm for its adaptation to the AESUM program complex with the function to ensure the probabilistic predicted operating condition of the bridges in the automatic mode is presented. This makes it possible, even in case of unsatisfactory performance of surveys, to have the predicted lifetime of bridges at the required time. For each bridge element it is possible to determine the residual time of operation that will allow predict the state of the elements of the structure for a certain period of time in the future. Significant interest for specialists calls for the approaches to the development of orientated perspective plans for bridge inspection and monitoring of changes in the operational status of bridges for 2009-2018 in Ukraine. For the analysis of the state of the bridge economy, the information is available on the distribution of bridges by operating state related to the administrative significance of roads, by road categories and by materials of the structures. Determining the operating state of the bridge is an important condition for making the qualified decisions as regards its maintenance. The Analytical Expert Bridges Management System (AESUM) which is implemented in Ukraine, stores the data on the monitoring the status of bridges and performs the necessary procedures to maintain them in a reliable and safe operating condition. An important result of the work is the ability to determine the distribution of bridges on the public roads of Ukraine, according to operating conditions established in the program complex of AESUM, which is presented in accordance with the data of the current year. In conditions of limited funding and in case of unsatisfactory performance of surveys, it is possible to make the reasonable management decisions regarding the repair and the reconstruction of bridges. Keywords: bridge management system, operating condition, predicted operating condition, model of degradation, bridge survey plan, highway bridge.

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