Academic literature on the topic 'Light-weight building construction'

Phase Change Materials (PCMs) have been considered for thermal storage in buildings since 1980’s. With the advent of PCM implemented in gypsum board, plaster, concrete or other wall covering material, thermal storage can be part of the building structure even for light weight buildings. The new techniques of microencapsulation opened many possibilities in buildings applications. An innovative concrete with PCM was developed using a commercial microencapsulated PCM, with a melting point of 26°C and a phase change enthalpy of 110 kJ/kg. The first experiment was the inclusion of a microencapsulated PCM in concrete and the construction of a small room-sized cubicle with this new PCM-concrete. A second cubicle with the exact same characteristics and orientation, but built with standard concrete, was located next to the first one as the reference case. In 2005 and 2006 the behaviour of such cubicles was tested. Later on, a Trombe wall was added to the cubicles to investigate its influence during autumn and winter. The increase of the numbers of hours at which the cubicle with PCM is within the comfort zone defined by ASHRAE with respect to the cubicle without PCM is given.

LSBWR (Long operating cycle Simplified BWR) is a modular, direct cycle, light water cooled, and small power (100–300MWe) reactor. The design considers requirements from foreign utilities as well as from Japanese. LSBWR is currently being developed by Toshiba Corporation and Tokyo Institute of Technology. Major characteristics of the LSBWR are: 1) Long operating cycle (target: over 15 years), 2) Simplified systems and building, 3) Factory fabrication in module. From the perspective of economic improvement of nuclear power plant, it is needed to shorten the plant construction period and to reduce building volume. In designing LSBWR building, a new building structure, where the hull structure of a ship is applied to floors and walls of LSBWR has been studied. Since the hull structure is manufactured at a shipyard, building module that includes plant equipment becomes possible. The application of the hull structure, which can make large modules at a shipyard, is an effective solution to the lack of laborer and economic improvement. LSBWR is a small size BWR, turbine is smaller size and lighter weight than medium or larger size plant. Then, it has been studied to install a reactor and a turbine in the same building for decreasing building volume. From the view point of standardization, whole building is supported by three dimensional seismic isolation mechanism.

Aluminum alloys because of their high strength to weight ratio have various applications as structural material in railways, ship building, aeronautics, construction, and consumer appliances. This increased use of aluminum alloys calls for more efficient and reliable welding processes which has always represented a great challenge for designers and technologists. AA-6061 Aluminum Alloy (Al-Mg-Si) is widely used in the aircraft industry and has gathered wider acceptance in the fabrication of light weight structures. The preferred welding process for this alloy is Tungsten Inert Gas (TIG) process due to their comparatively easier applicability, high yield, and better economy. Major difficulties are associated with this type of welding process, such as, the presence of tenacious oxide layer, high coefficient of thermal expansion, solidification shrinkage, solubility of hydrogen, and other gases in the molten state. Furthermore, problems such as decay of mechanical properties due to phase transformation and softening can occur in the heat-affected-zone (HAZ). Post weld heat treatment can be used to improve the strength of the HAZ for heat-treatable alloys like AA-6061. Hence, the major objectives of this work was to conduct a systematic study and gain an in-depth understanding of the effect of post-weld heat treatment (PWHT) of these joints on tensile properties, micro hardness, microstructure, and fracture surface morphology of butt-welded joints. It was found that of all the PWHT processes, Age-hardening (AH) resulted in superior mechanical properties and hardness. The reason for this enhanced strength has also been studied from metallurgical point of view. Microstructure and fracture surface of the tensile tested specimens were studied using light microscope and scanning electron microscope, respectively. Correlation has been drawn between the tensile test results, microhardness and the metallurgical results. It was found that the uniformly dense precipitation of fine Mg2Si, and the lack of precipitate-free zone could be the reason for the superior results found.

Concrete is a major material used in the construction of buildings and structures in the world. Gravel and sand are the major ingredients of concrete but are non-renewable natural materials. Therefore, the utilisation of palm oil clinker (POC), a solid waste generated from palm oil industry is proposed to replace natural aggregate in this research to reduce the demand for natural aggregates. One mix of ordinary concrete as control concrete; while four mix proportions of oil palm clinker concrete were obtained by replacing 25 %, 50 %, 75 %, and 100 % of gravel and sand of control concrete with coarse and fine oil palm clinker respectively by volume, with same cement content and water cement ratio. Compressive strength test was carried out of concretes with different percentages of oil palm clinker; whereas water absorption test according to respective standard, were carried out to determine the durability properties of various mixes. Based on the results obtained, the study on the effect of percentage of clinker on strength and durability properties was drawn. According to ACI classification of light weight concrete only the 100 percentage replacement can achieve the definition of light weight concrete since its density less than 1900 kg/m3 and strength larger than 17 MPa. Eventually the 25 % replacement of the normal aggregate by the OPC will improve the strength and durability of the concrete.

<p>For the use of popular GFRP composite materials for the construction of considerable-size facilities such as, for instance bridges, it is required to manufacture the finished prefabricated composite units joined together. The various manufactured composite panels are used in bridge decks on the bridges. The panels have system connections and allow them to be quickly assembled. One of the examples are the th-5 panels manufactured by a pultrusion method, used in bridges and helicopter pads. Considering the exceptionally light, fire-resistant and heating bridge deck the composite panel constitutes an attractive alternative for aluminium in helicopter pads and sidewalks for pedestrians and cyclists on bridges. Passenger drones that are expected to be used in the near future will require light-weight landing field structures located on the existing buildings.</p><p>The developed author’s innovative system for extending the existing bridges by adding sidewalks for pedestrians and cyclists (Fig.1) is called the “velo-pont” and is based on the use of composite panels. The individually designed click-clack connection is an innovative author’s solution for longitudinal joining of panels. Such solution can successively be used for bridges with a long sidewalk, even several hundred meters long.</p><p>The proprietary solution has been examined and tested. A prototype has been made to a real scale. The system solution has been already used in practice for several bridges in Poland.</p>

Pneumatic actuators used in devices that, by their function require light weight and small size such as orthotics, can benefit from the inclusion of accumulators to harness and recycle energy normally lost in exhausted gases. In order for an accumulator to provide benefits to these small systems, they must possess relatively high gravimetric and volumetric energy densities with adequately high efficiencies as compared to conventional accumulators, like traditional spring piston accumulators. Constructing accumulators that primarily use strain as the primary energy storage method can provide the energy storage capacities and efficiencies needed, as well as a better pressure-volume relationship than a fixed-volume accumulator. This paper outlines the behavior of an elastomeric strain accumulator constructed using natural rubber tubes as the material for an accumulator. Tube shaped accumulators fill to a preset maximum diameter, constrained by a rigid shroud so that the material’s yield strength is not approached and to control the manner in which the accumulator expands. Controlling the manner of expansion for the accumulator allows a relatively constant pressure to be used through the majority of the fill cycle. Natural rubber accumulators were experimentally evaluated and characterized for their energy storage efficiencies over a range of different parameters allowing basic design criteria to be created for use in building accumulators tailored to specific system requirements.

The new Milwaukee Streetcar system has been in the planning, design and construction phases for over 10 years and on November 2, 2018, operations with a combined overhead contact system and streetcar battery power commenced ushering in a new era of growth for the City of Milwaukee. Many challenges in the design and construction of the overhead contact line and power system were encountered during this time period including budgetary constraints, multiple pole location changes, underground obstacles, low clearance bridges, alignment changes, utility conflicts, and changing vehicle requirements. The line was originally designed for pantograph operation but soon adapted for pole/pantograph current collection and then changed back to pantograph only current collection during the final design. The original design consisted of underground feeder cables to supplement a 4/0 contact wire but eventually not utilized due to budgetary constraints. Instead, a larger 350 kcmil contact wire was used with no paralleling feeder cables. The added weight of a 350 kcmil wire with wind, ice and low temperatures created high forces in the overhead contact system (OCS) leading to challenges in pole and foundation design where compliance to the National Electrical Safety Code (NESC) was required. The OCS style originally proposed and finally constructed used an inclined pendulum suspension (IPS) system that was constant tensioned with rotating springs deemed by the installing contractor superior to balance weights. The pendulum system was chosen as it is simple, lightweight, less visually obtrusive, and more economical than other suspension systems such as stitch and steady arm that are being used on other streetcar or light rail systems. IPS has provided Milwaukee with an excellent operating overhead contact system. Buildings along the route that were not historic structures were utilized where possible for span wire attachment but in many locations long bracket arms up to 40 feet long had to be used requiring special designs to keep the size of the pipes standard with the rest of the system. Challenges arose at low bridge underpasses where the contact wire had to be below required code height and special precautions had to be undertaken. Other areas such as the St. Paul Lift Bridge proved challenging as well where special electrically interlocked OCS devices were initially designed to de-energize the overhead wires and is further discussed with the reasoning for their use. This paper outlines the phases of design, the changes to the design that occurred over time, the challenges encountered to the OCS design, the method of design, and the final disposition of the design for construction. It further outlines the construction of the system and problems encountered with poles, foundations, bracket arms, traction power substations, contact wire, feeder cables, and winter conditions affecting the integrity of these structures and how some of these problems were solved.