STRUCTURAL STRESS METHOD FOR FATIGUE DESIGN OF CONCRETE FILLED STEEL TUBULAR T-JOINTS UNDER AXIAL LOADING

Steel tubular structural members are being widely used in various engineering structures. The steel tubular joints will have fatigue problem when subjected to repetitive loading. Fatigue strength is one of the key factors that control the design of steel tubular joints in structures subjected to frequent loading. Research has shown that concrete filling of the steel tubes can effectively reduce stress concentrations at the joint. In this study, the structural stress method which involves the through-thickness stress distribution, has been employed to estimate the fatigue life of concrete filled steel tubular (CFST) T-joints under axial loading in the brace. A Finite Element (FE) model has been developed using ABAQUS. The three-dimensional 8-node hexahedral element has been employed in the FE model. The structural stresses have been extracted and the fatigue life of the joint has been estimated. The results have been verified using experimental results reported in the literature. The current study showed that the structural stress method can effectively predict reliable fatigue life in concrete filled steel tubular (CFST) T-joints.

BIOCLIMATIC OPTIMIZATION: SKYLIGHT GROUND FLOOR NEW BUILDING, UDLA PARK TORRE II

When high thermal comfort and energy efficiency are provided in an academic environment many beneficial effects on student’s comfort, performance, productivity, and health are shown. The research provides a parametric airflow evaluation of a skylight in a ground floor of new educational building assuming a variation of 4 stages with eight scenarios for the admissions office. By means of the bioclimatic analysis, Predicted Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD) indices, the best internal airflow performance for the study area applying natural ventilation is achieved with the air flow optimization. A minimum area of 1.79 m has been established for extraction and movement of the internal flow, both with the natural extraction louvers system measuring 12 inches by 60 inches and the 18 inches by 60 inches, they work properly. However, the 18 inches by 60 inches system has better effectiveness as it has fewer louver units to be placed, is more homogeneous, avoids turbulence and provides better air extraction. In addition, by having fewer louver units distributed along the length of the skylight, it will allow the operation to be more controlled during the operation of the building. The use of 8 louvers of those proportions, with an individual effective area of 0.23 m and a total of 1.84 m was recommended in accordance with the results obtained.

INNOVATIVE PRE-FABRICATED CONNECTORS FOR BAMBOO ARCHITECTURE

Bamboo is the natural construction material that has become the trend for the sustainable architecture, due to its renewability. Bamboo connections are considered the most difficult process that consumes construction time. This study is the design experiment how innovative connections can expedite the fabrication and their performance. The study deals with the design of connection prototypes for bamboo framing and tests their performance in actual construction. Connectors are designed into the receivers and the nozzles. Receivers act like the female connector. They are receptors at foundation to transfer loads to ground. The nozzles are the male connector that looks like an extruder attached to the end of structural members to connect to the receivers. Nozzles are offered in both a single culm and split bundles. The experiment also designed the straps for bamboo splits, to wrap the split together into one bundle. Steel connectors are introduced to initiate the bamboo construction as pre-fabrication process, yet the strength of connections is maintained. These prototypes are also applied to actual construction to verify the constructability, performance, and architectural applications. It is found that connectors are effective to minimize construction time, but still have other limitation. The study took lesson learned to design more permanent connectors to solve all restricted issues. Finally, innovative connectors were created into many variety forms for fabrication. They can also perform greatly in strength and attractive look. These findings can motivate architects to explore possibility for bamboo architecture in pre-fabrication process, and to be more innovatively and effectively.

EFFECTS OF REPLACING CEMENT BY DATE PALM TREES WASTES ON CONCRETE PERFORMANCE

This paper was studying the effects of palm tree wastes on the behavior of the concrete to reduce cement content in the concrete to ensure a sustainable environment. Both fibers of palm tree and the ash of palm tree leaves are used in this study considering different percentages of palm tree wastes, which are replaced the cement, to investigate both of workability and strength of the concrete. Also, the combination of palm tree leaves ash and fibers of palm trees is investigated. The slump and compression tests are carried out to evaluate both workability and concrete strength. The palm fibers were reducing the workability of concrete at both of different percentage of replacement and different fiber lengths. The slump is reduced by 26.667% at 2 cm fibers length and it is completely lost at 5 cm length fibers at the same percentage of replacement of 5% of the cement content. The palm fibers were weakening concrete compressive strength at different percentages and different fiber lengths. Palm leaves ash was enhancing concrete workability and concrete compressive strength.

DESIGN OF A CAPABILITY MATURITY FRAMEWORK (CMF) FOR RESILIENT INFRASTRUCTURE MANAGEMENT (RIM) IN RURAL MUNICIPALITIES IN SOUTH AFRICA

Cities worldwide are often faced with manpower capacity deficits to develop and manage infrastructure. There remain discrepancies between global SDG aspirations and national realities in most Sub-Saharan African (SSA) countries in achieving universal access to services by 2030. Service provision in South African municipalities has been beset by deficient engineering skills (ES) and infrastructure management (IM) capabilities as a result. IM capabilities are crucial enablers for continuous service provision. Yet, on the contrary, in South Africa, nearly 58% of all engineering professionals are found in metropolitan municipalities, with some 9% placed in urban municipalities. Furthermore, 67% of all the professionals, technicians, and engineers in the municipal system countrywide are employed in only 27 of the 257 municipalities. There is a notable lack of resilient IM in South African rural (category B4) municipalities. Likewise, current Capability Maturity Models (CMM) are rendered inappropriate for rural municipalities. Thus, this on-going research contends for prominent structural shifts in improving IM capabilities in rural municipalities, arguing that previous engineering capacity building programmes omitted the resilience component in their design parameters. The on-going study aims to design a capability maturity framework for resilient IM in rural municipalities following sequential multi-data collection procedures, pilot interviews with experts, then a survey questionnaire. Descriptive statistics will be used to analyze the survey data and thematic analysis for analyzing the qualitative data. In terms of contribution to academia, it is hoped that the on-going study would assist category B4 municipalities to close the resilience gap in infrastructure management.

SEISMIC PERFORMANCE OF GFRP-RC RECTANGULAR COLUMNS: NUMERICAL STUDY

Composite materials like glass fiber-reinforced polymer (GFRP) is becoming widely acceptable to be used as a reinforcing material due to its high ultimate tensile strength-to-weight ratio and excellent resistance to corrosion. However, the seismic behavior of GFRP-reinforced concrete columns has not been fully investigated yet. This paper presents the results of a numerical analysis of full-size GFRP-RC rectangular columns under cyclic loading. The simulated column depicts the lower part of a building column between the foundation and the point of contra-flexure at the mid-height of the column. GFRP reinforcement properties and concrete modeling based on fracture energy have been incorporated in the numerical model. Experimental validation has been used to examine the accuracy of the constructed finite element models (FEMs) using a commercially available software. The validated FEM was used to perform a parametric study, considering several concrete strength values and axial load levels, to study its influence on the performance of the GFRP-reinforced concrete columns under cyclic loading. It was concluded that the hysteretic dissipation capacity deteriorates under high axial load level due to severe softening of the concrete. The FE results showed a substantial improvement of the lateral load-carrying capacities by increasing concrete compressive strength.

MAINTENANCE MANAGEMENT DETERMINANTS APPRAISAL OF HOSPITAL BUILDINGS

This research examines the maintenance practice of hospital buildings in Malaysia. Recently, the increment of hospital buildings’ accidents has affected its performances as a result of determinants. However, the maintenance practice employed in the hospitals has a direct impact on the performance of hospital buildings. The fast-growing population of Malaysia necessitates proactiveness on the part of the government regarding the provision of efficient healthcare and ensuring the wellbeing of the citizenry. In this regard, the state of hospital buildings is inextricably linked to quality healthcare. This study evaluates the determinants that impair the quality of hospital buildings in Malaysia in order to improve their efficiency and preempt the avoidable building pitfalls through effective maintenance management. The survey questionnaire was used in order to achieve the objective of this study to users of hospital buildings, the outcomes sought after concerned building component issues such as finishes, cleanliness, aesthetics, ventilation and other determinants that affected the performance of the hospital buildings. The results showed that specific determinants including lighting, ventilation, fire alarms, fire extinguisher signage, floor conditions, lifts and quality of air depreciate the performance of hospital buildings. In addition, the procurement methods of maintenance work are completely outsourcing in hospitals and combinations of outsourcing and in-source methods in a private hospital. Moreover, the study found that the current methods of maintenance management adopted for hospital buildings remain typically corrective. This has always resulted in deprived user satisfaction, unproductive service delivery, and the prolongation of diverse maintenance problems.

CLASSIFICATION OF CLAIM-CAUSING EVENTS ACCORDING TO THEIR COMPLEXITY

The increasing complexity of construction projects has inevitably led to site managers are facing ever more complex claims. As a result, they are increasingly occupied with claim management. Their primary task, however, is to carry out the project and claim management is considered a secondary task. Furthermore, site managers often lack both the know-how and the resources required for handling complex claims. Attaining a successful outcome for a claim, demands stringent causal evidence for each single event linked to its effects. This makes documentation and quantification of a complex claim exceptionally difficult. Site managers tend to underestimate the complexity of a claim-causing event and as a consequence may often be too late in notifying internal company experts or external consultants focusing on claim management. This paper aims to categorize deviations causing a claim according to its complexity at the time of its occurrence. To do so, a quantitative survey was handed out to site managers in the Austrian construction industry. Based on the findings, the authors designed a decision-making matrix to classify claim-causing events according to their complexity. This will allow site managers to take necessary measures processing a claim and mitigate possible disputes.

OBSTACLES OF IMPLEMENTING GREEN MAINTENANCE MANAGEMENT IN HOSPITAL BUILDINGS

Demand for green hospital buildings is increasing. While some hospital buildings were designed and constructed as green buildings, many hospital buildings have been upgraded to comply with the green requirements. Green hospital buildings require green maintenance practice. In comparison, procuring green buildings is easy as compared to green maintenance. Through unstructured interviews involving 3 hospitals, this research investigated the complications in the implementation of green maintenance in hospital buildings. The research found that lack of awareness, financial constraints/government support, new technologies, and top management support were the major obstacles toward the implementation of green maintenance. The results also confirmed that the maintenance of hospital buildings is corrective, reactive, and cost-driven. The salient finding from this research is that the maintenance organizations have a poor understanding of the concept of green maintenance practices. Saving energy costs are the main purpose of implementing green maintenance in hospitals. From an ontological point of view, the main findings of this research on the constraints of the implementation of green maintenance are generalizable to other types of buildings in and outside of Malaysia.

EXPERIMENTAL STUDY ON USE OF FALL PREVENTION MEMBERS IN WALL AND COLUMN DEMOLITION

At demolition sites in Japan, columns and walls are pulled down and demolished by heavy machinery or wire ropes. In a small-scale building in urban areas, columns and walls are pulled down by wire ropes. Before pulling down, workers damage the bottom part of the columns and walls for weakening them. However, if the damage of the columns and walls are too much, they fall down before use of wire ropes. As a result, they may crush workers. In this study, a fall prevention material was proposed with its installation method and verified its effectiveness by experiments. In an experiment of this study, steel pipes for supporting 3m-column were examined. The steel pipes were installed diagonally to the column. The column was loaded horizontally. We measured load and deformation until the steel pipe failed. As a result of experiments, it was found that the steel pipe buckled or the bolt supporting the steel pipe damaged. We concluded that this method is effective because the steel pipes were found to be sufficiently strong against the load generated in the steel pipes when the columns fell.