scholarly journals Experimental Investigations on Ultimate Behavior of Fabricated Mobile Scaffolds

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 851
Author(s):  
Heesoo Kim ◽  
Jeonghyeon Lim ◽  
Jeonghwa Lee ◽  
Young Jong Kang ◽  
Seungjun Kim
Keyword(s):  
Evaluation Methods ◽  
System Level ◽  
Structural Safety ◽  
Structural Performance ◽  
Experimental Investigations ◽  
Rigorous Evaluation ◽  
Effective Evaluation ◽  
Test Models ◽  
Behavior Characteristics ◽  
Structural Behaviors

A fabricated mobile scaffold has various components, including vertical members, horizontal members, braces, work plates, and castor wheels. In Korea, the structural performance of each member must be validated based on member-level structural safety criteria; this means that rigorous evaluation methods are required to secure the system-level structural safety of the fabricated mobile scaffold. To suggest rational system-level structural safety criteria and effective evaluation methods, the characteristics of the structural behaviors of the assembled structure must be investigated first. Unlike other temporary equipment, it is a product that requires convenience of use and ease of movement. Therefore, to secure the safety and usability of the structure, it is necessary to evaluate the ultimate behavior of a mobile scaffold fabricated with various material and structural types. In an experimental study, the ultimate mode and load-bearing capacity were investigated, and the appropriateness of the required performance of the mobile scaffold was reviewed. Three types of experimental test models with different materials (steel and aluminum) and stories (single-story and three-story erection) were selected and examined for vertical loads. Based on the experimental results, the ultimate behavior characteristics of the fabricated mobile scaffold were analyzed, and the ultimate load was identified.

scholarly journals Suggestion of Safety Certification Standards and Performance Evaluation Methods for Fabricated Mobile Scaffold in South Korea

2021 ◽  
Vol 19 (1) ◽  
pp. 133
Author(s):  
Heesoo Kim ◽  
Jeonghyeon Lim ◽  
Jeong-Hun Won ◽  
Jun-Hyuk Kwon ◽  
Seungjun Kim
Keyword(s):  
Performance Evaluation ◽  
Carrying Capacity ◽  
Evaluation Methods ◽  
Structural Safety ◽  
Structural Performance ◽  
Load Carrying Capacity ◽  
Safety Certification ◽  
Load Carrying ◽  
Certification Standards ◽  
And Performance

At construction sites, various types of temporary equipment and structures are used for safety and work efficiency. However, various temporary equipment-related accidents frequently occur for many reasons, including inappropriate installation, usage, and material and structural imperfections. A mobile scaffold is one of the most commonly used indoor temporary equipment for work in high places. In general, the main structural members of the mobile scaffold, such as the mainframes, horizontal members, braces, caster wheels, outriggers, and handrails, are installed on the construction site for this purpose. This means that the load-carrying capacity of the equipment can vary depending on the assembly details. In Korea, there are safety certification standards applied for frequently used temporary equipment, such as scaffolds and shoring. However, the standards concern the strength criteria for the member itself, rather than the global load-carrying capacity. Therefore, it is difficult to review whether the fabricated mobile scaffold has sufficient load-carrying capacity, or to confirm the structural safety considering the various uncertainties affecting the structural performance. In this study, rational safety certification standards and evaluation methods are suggested for fabricated mobile scaffolds. The suggested safety certification standards present structure-level criteria for checking the load-carrying capacity, horizontal stiffness of the structure, and overturning risk. It is expected that the structural performance for safety can be directly checked based on the suggested safety certification standards and performance evaluation methods during the safety certification stage.

Mechanical performance of polyester pin-reinforced foam filled honeycomb sandwich panels

2018 ◽  
Vol 25 (4) ◽  
pp. 797-805 ◽  
Author(s):  
R.S. Jayaram ◽  
V.A. Nagarajan ◽  
K.P. Vinod Kumar
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Flexural Rigidity ◽  
Sandwich Panels ◽  
Interfacial Strength ◽  
Structural Performance ◽  
Experimental Investigations ◽  
Honeycomb Sandwich ◽  
Foam Filled ◽  
Pin Reinforcement

Abstract Honeycomb sandwich panels entice continuously enhanced attention due to its excellent mechanical properties and multi-functional applications. However, the principal problem of sandwich panels is failure by face/core debond. Novel lightweight sandwich panels with hybrid core made of honeycomb, foam and through-thickness pin was developed. Reinforcing polyester pins between faces and core is an effectual way to strengthen the core and enhance the interfacial strength between the face/core to improve the structural performance of sandwich panels. To provide feasibility for pin reinforcement, honeycomb core was pre-filled with foam. Mechanical properties enhancement due to polyester pinning were investigated experimentally under flatwise compression, edgewise compression and flexural test. The experimental investigations were carried out for both “foam filled honeycomb sandwich panels” (FHS) and “polyester pin-reinforced foam filled honeycomb sandwich panels” (PFHS). The results show that polyester pin reinforcement in foam filled honeycomb sandwich panel enhanced the flatwise, edgewise compression and flexural properties considerably. Moreover, increasing the pin diameter has a larger effect on the flexural rigidity of PFHS panels. PFHS panels have inconsequential increase in weight but appreciably improved their structural performance.

scholarly journals Structural Safety Analysis of the Aqueducts “Coll De Foix” and “Capdevila” of the Canal of Aragon and Catalonia

2018 ◽  
Vol 3 (4) ◽  
pp. 48
Author(s):  
Albert de la Fuente ◽  
Vicente Alegre ◽  
Ana Blanco ◽  
Teresa Cavero ◽  
Roberto Quintilla
Keyword(s):  
Civil Engineer ◽  
Cross Section ◽  
Structural Reliability ◽  
Safety Analysis ◽  
Structural Safety ◽  
Structural Performance ◽  
Design Considerations ◽  
User Communities ◽  
The Cross

The Canal of Aragon and Catalonia (CAC) is 134 km long and irrigates 105,000 ha (131 irrigation user communities) and it is owned by the River Ebro’s Water Agency. The aqueducts are located between km 67 and 71 of the canal and were designed by the civil engineer Félix de los Ríos Martín in 1907. The cross-section of both aqueducts, Coll de Foix and Capdevila, was extended within the framework of the project by Fernando Hué Herrero in 1962 in order to reach design flows of 26.1 m3/s and 25.7 m3/s, respectively. The structural performance of the aqueducts has been satisfactory; nevertheless, the hydraulic capacity has reduced over the years. As a result, the irrigation user communities have expressed the need to extend the cross-section of the aqueducts to meet the irrigation demands. Given the age of the structure and the different design considerations at the time, it is paramount to verify the structural reliability of the aqueducts in the new load configuration. Therefore, the objective of this contribution is to present the structural safety analysis conducted and to describe the new extended cross-section for both aqueducts (maintaining the original structural typology).

Influence of the Parameter of Ductility of Reinforcing Steel on the Behaviour of a Narrow Three-Span Reinforced Concrete Slab Based on Experimental Investigations

2015 ◽  
Vol 240 ◽  
pp. 218-224 ◽  
Author(s):  
Mirosław Wieczorek
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Load Capacity ◽  
Experimental Tests ◽  
Experimental Investigations ◽  
Building Structures ◽  
Reinforced Concrete Slab ◽  
Tension Member ◽  
Test Models ◽  
Reinforced Steel

In the time of the exploitation of building structures frequently situations do occur, in which due to failures they are exposed to much higher loads than has been originally predicted. In a state of emergency due to overloading of the structure, significant reserves of load capacity may be appear in the case of a self-acting tension member work. The aim of the paper was to demonstrate the influence of reinforced steel parameters and its quantity on the mechanism of destruction of four three-span models of reinforced concrete strips with the dimensions 7140×500×190 mm. The paper contains the description of the test stand and test models and the results of experimental tests which were compared with the results of the calculations based on traditional methods.

scholarly journals Evaluation of Wood Coverage on Building Facades Towards Sustainability

2019 ◽  
Vol 11 (5) ◽  
pp. 1407 ◽  
Author(s):  
Hongpeng Xu ◽  
Jing Li ◽  
Jianmei Wu ◽  
Jian Kang
Keyword(s):  
Eye Tracking ◽  
Orthogonal Design ◽  
Evaluation Criteria ◽  
Evaluation Methods ◽  
Design Experiment ◽  
Test Models ◽  
Building Facades ◽  
Physical Variables

This study explores the acceptance of different wood coverages on building facades with the aim of optimization of materials, and in turn improving overall sustainability. It firstly develops the principal physical variables and evaluation criteria; then, test models are created using an orthogonal design experiment; finally, two evaluation methods are used to comprehensively test acceptance, based on a questionnaire and an eye-tracking study. The results show that: (1) The effects of the amount of wood coverage and the wood patterns are significant, whereas the effect of material combinations is insignificant. (2) The acceptance of building facades is at the highest level when the amount of wood coverage is 65%. (3) The amounts of wood coverage for facades in the range of 35% to 50% are effective when designing the facade of wood buildings, in order to implement the dual targets of saving wood and higher acceptance.

Experimental Investigations on Aero-Thermal Interaction of Film Cooling Airs Ejected From Multiple Holes: Shallow Hole Angle

2012 ◽  
Author(s):  
Kamil Abdullah ◽  
Ken-ichi Funazaki ◽  
Hisato Onodera ◽  
Takeomi Ideta
Keyword(s):  
Film Cooling ◽  
Experimental Investigations ◽  
Contour Plot ◽  
Test Model ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Test Models ◽  
Thermal Investigations ◽  
Baseline Test ◽  
Pitch Distance

This paper presents thermal and aerodynamics investigations of multiple cooling holes with shallow hole angle. Three test models have been considered namely TMA, TMB and TMG. TMB is acting as the baseline test model having 35° hole angle cooling holes. The other two test models; TMA and TMG, have a shallow hole angle of 20° with different lateral pitch distance of 6D and 3D respectively. Total of twenty conventional cylindrical cooling holes have been arranged to form a five times four matrix. All three test models have been considered in the thermal investigations with only the shallow hole angle test models have been considered for the aerodynamics investigation. The film cooling effectiveness has been measured by means of infrared thermography while 3D-LDV has been utilized for the flowfield measurements. The measurements were carried out at single Reynolds number base on the hole diameter of 6200 at three different blowing ratios of 0.5, 1.0 and 2.0. All three blowing ratios have been considered in the thermal investigations with only the latter two blowing ratios were considered in the aerodynamics investigation. The results are presented in the form of contour plot of various variables including film cooling effectiveness, normalized u, v, and w velocities, normalized root mean square of u velocity and Reynolds stress tensors. Distribution of laterally average film cooling effectiveness along the x-axis are also presented, showing that the 20° hole angle cooling holes provide a very promising results particularly at high blowing ratio. The velocities contours clearly capture the flow structure of the film cooling jets, along with the effects of blowing ratios and lateral pitch on the flowfield.

scholarly journals Sensitivity analysis of the influences of mortar aging and loss on the structural performance of masonry arch aqueducts

2021 ◽  
Vol 300 ◽  
pp. 01022
Author(s):  
Jiang Hu ◽  
Fuheng Ma
Keyword(s):  
Structural Integrity ◽  
Significant Proportion ◽  
Deep Understanding ◽  
Sensitivity Analyses ◽  
Structural Safety ◽  
Stone Masonry ◽  
Structural Performance ◽  
Structural Behaviour ◽  
Masonry Arch ◽  
And Performance

As commonly used canal system structures, masonry arch aqueducts constitute a significant proportion of Chinese old irrigation infrastructures. Most of these existing aqueducts are well over 50 years old, the deterioration of their constituent materials over time, as well as the development of other defects, significantly affects the mechanical responses of these structures. A deep understanding on the dominant factors that influence the structural safety behaviour of masonry arch aqueducts is essential for determining maintenance and strengthening strategies. Taken the Zhaimen masonry aqueduct in the famous Red Flag Canal as a case study, sensitivity analyses of the influences of mortar aging and loss on the structural performance were carried out. The aqueduct, with unknown geometric dimensions and uncertain physical and mechanical parameters, has defects such as the arch ring detaching from the upper structure and the continuous loss and falling of mortar. The discrete element method (DEM) was employed to analyse the structural behaviour. The results show that the upper structure and the supporting structure are stable under the no bond strength condition. When the mortar is lost locally, the vault position is the most dangerous, followed by the arch shoulder, and then the arch foot part. The mortar loss, manifested as denseness reduction, greatly affects the aqueduct stability. Conversely, the deterioration of the mechanical properties of the mortar, caused by weathering and Calcium ion dissolution due to ambient environment and aqueduct leakage, has relatively little impact on the structural safety. Supplementary grouting of the mortar between the stone masonry should be timely carried out to maintain the structural integrity to ensure the overall stability of the structure. The proposed approach can provide a reference to structural diagnosis and performance assessment for similar structures.

scholarly journals Repair of Fire-Damaged Reinforced Concrete Members with Axial Load: A Review

2019 ◽  
Vol 11 (4) ◽  
pp. 963 ◽  
Author(s):  
Jun Zhou ◽  
Lu Wang
Keyword(s):  
Reinforced Concrete ◽  
Residual Strength ◽  
Axial Load ◽  
Common Knowledge ◽  
Structural Safety ◽  
Experimental Investigations ◽  
Great Loss ◽  
Concrete Members ◽  
Reinforced Polymer ◽  
Structural Fires

It is common knowledge that structural fires have led to a great loss of buildings and damage to property in the past two decades. Therefore, there is a growing need to provide approaches for post-fire repair of structural members to enhance their structural safety. This paper presents a state-of-the-art review on the repair of fire-damaged reinforced concrete (RC) members with axial load. The investigations into the effects of loading method, physical dimension and bonding behavior on the residual strength of members are presented. In the meantime, the available experimental investigations on the performance of fire-damaged RC members with axial load repaired with concrete jacketing, steel jacketing and fiber-reinforced polymer (FRP) jacketing are summarized. Moreover, models for predicting the residual strength of fire- damaged columns are reviewed.

Experimental Investigations for Characterization and Analysis of Rake Face of the WC-Co Inserts Using Taguchi Method

2010 ◽  
Author(s):  
C. L. V. R. S. V. Prasad ◽  
S. V. Ramana ◽  
S. Srikiran ◽  
K. Ramji
Keyword(s):  
Taguchi Method ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Flow Patterns ◽  
System Level ◽  
Experimental Investigations ◽  
Work Piece ◽  
Rake Face ◽  
Experimental Conditions ◽  
Chip Flow

In order to improve the performance of the cutting tool, it is required to model the metal cutting process at the system level. To predict and enhance the cutting tool performance the primary requirement of the system is the efficiency of the model explaining the interactions at the tool chip interface. The predominating parameters which influence the development of the system are work piece material and machining variables or sometimes both. Further the development of low cost methodology to study the chip tool interactions with minimum amount of testing is of more importance. Major part of the work is emphasized on the investigation and characterization of various zones on the rake face of tungsten carbide inserts. Tests have been carried out by machining AISI 1040 steel using WC inserts with variable dry conditions examining the chip flow phenomenon on the rake face of considerable number of samples. Taguchi method is adopted for the design of experimental conditions. Results have shown an acceptable chip flow patterns and authors were able to quantify the wear zones on the rake face. The rake face is then characterized to represent all the possible cases of chip flow patterns, crater wear and chipping of the cutting edge. Side and end cutting edges are taken as datum lines for locating the wear zones. The quantification and locations of the wear zones might help the researchers and tool makers to concentrate more on the defined areas instead of the rake face in total.

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