Academic literature on the topic 'Superimposed dead load'

Abstract The aim of this work was to determine stresses in the wall of a buried empty gas pipeline caused by the weight of backfill as well as by heavy-duty vehicles crossing the pipeline, and, on their basis to assess the applicability of protective sleeves. A buried pipeline with zero internal pressure of transported medium (empty pipeline) differs from an unburied pipeline by the vertical load due to the weight of the backfill which causes an ovalness of the circular cross section of the pipeline. This leads to the rise of through-wall bending stresses with the tensile stress at the outside surface at the 3 and 9 o´clock positions and compressive stress at the inside surface. At the 6 and 12 o´clock positions the stresses are tensile at the inside surface and compressive at the outside surface. The current depth of soil cover above gas pipelines is 0.5 m. For pipes DN500, t ~ 6.5 mm the through-wall bending stress is found to be σb ≈ ±10 MPa. In comparison with the yield stress of pipeline material, this stress is negligible. The situation is changed when heavy-duty vehicles cross the pipeline. For example, when a MAN truck with the mass load 3270 kg acting on a single wheel of the front axle crosses this pipeline, the pressure transmitted to the pipe will cause the through-wall bending stress σb ≈ ±76 MPa. This stress is superimposed to that of the backfill to give the total value ±86 MPa. When dead loads, imposed by backfill cover, together with live loads, caused by truck-wheel loads, are excessive a crushing of side walls of the pipeline and/or ring buckling of the pipe cross section can happen.

Indonesia is a country prone to earthquakes because it is located at the confluence of the Pacific and Trans-Asiatic Circum. Padang is included in the 5-6 earthquake area (KDS E & F), which is an area that has the potential for an earthquake accompanied by the possibility of a tsunami., comfortable and safe against the dangers of an earthquake or tsunami. The most influential factor in the planning of high-rise building structures is the strength of the building structure itself, where this factor is closely related to the safety and resilience of the building in holding and accommodating the loads acting on the structure. Instability in the structure is a basic thing that must be avoided and considered for various types of building heights. An unstable structure when subjected to loads causes the structure to experience a greater deformation than a stable structure. One way that can be done to make the structure more stable is to combine the structure with Shear Walls. Shear wall systems can be used to withstand vertical forces such as gravity loads and horizontal/lateral forces such as earthquake and tsunami loads, thereby preventing excessive swaying of the structure. The use of shear walls is also intended so that when an earthquake and tsunami occurs, the lateral forces that affect the structure are not only resisted by the beam and column elements in the structure but are also resisted by the shear wall system. because the placement of the shear walls that are not appropriate causes the shear forces that occur in the columns and beams to be greater. The research object is multi-storey reinforced concrete buildings with variations in height of 5, 7, 10, 15 and 20 floors. Buildings 5, 7 and 10 floors are designed with an open frame system, while buildings with floors 7, 10, 15 and 20 are designed with a double system, namely open portals and shear walls as lateral load resisters. Open portals use a Special Moment Resisting Frame System (SRPMK) design, while shear walls use a Special Structural Wall System (SDSK) design. The calculated structural loads are dead loads, live loads, superimposed dead loads and earthquake loads. Building location in the city of Padang with moderate soil conditions. The strength and stiffness of structures with shear walls are higher than those without shear walls

Background: The treatment of osteochondral defects (OCDs) constitutes a major problem for orthopaedic surgeons. The altered mechanics and the cell types, with associated soluble factors derived from the exposed subchondral bone, are likely responsible for the mechanically and structurally inferior articular cartilage subsequently obtained as a repair tissue. There is therefore an unmet clinical need for bioresponsive biomaterials that allow cell delivery, reduce cell infiltration from the bone marrow, and support chondrogenesis in the presence of joint mechanical loading. Purpose: To develop a cell-laden injectable biomaterial, with bioadhesive properties, low cell invasion, and good mechanoresilience, in which simulated joint loading could induce tissue maturation through the production and activation of transforming growth factor beta 1 (TGF-β1). Study Design: Controlled laboratory study. Methods: Human bone marrow–derived mesenchymal stromal/stem cells were encapsulated in tyramine-modified hyaluronic acid (HA-Tyr) hydrogels, with crosslinking initiated by the addition of horseradish peroxidase (HRP) and various concentrations of hydrogen peroxide (H2O2; 0.3-2 mM). Cytocompatibility and biomechanical and adhesive properties were analyzed by live/dead staining, rheology, and push-out test, respectively. For multiaxial loading, cell-laden hydrogels were subjected to 10% compression superimposed onto a 0.5-N preload and shear loading (±25°) at 1 Hz for 1 hour per day and 5 times a week for 4 weeks. TGF-β1 production and activation were measured by enzyme-linked immunosorbent assay (ELISA). Results: The viscoelastic properties of the cell-laden HA-Tyr hydrogels, as crosslinked with different ratios of HRP and H2O2, were demonstrated for a range of cell densities and HRP/H2O2 concentrations. In the absence of serum supplementation, cell invasion into HA-Tyr hydrogels was minimal to absent. The bonding strength of HA-Tyr to articular cartilage compared favorably with clinically used fibrin gel. Conclusion: HA-Tyr hydrogels can be mechanically conditioned to induce activation of endogenous TGF-b1 produced by the embedded cells. HA-Tyr hydrogels function as cell carriers supporting biomechanically induced production and activation of TGF-β1 and as bioadhesive materials with low cell invasion, suggesting that they hold promise as a novel biomaterial for OCD repair strategies. Clinical Relevance: Leveraging physiological joint mechanics to support chondrogenic graft maturation in an optimized mechanosensitive hydrogel in the absence of exogenous growth factors is of highest interest for OCD repair.

Indonesia is one of the countries that is prone to earthquakes. In addition to the dead loads, superimposed dead loads, and live loads, the design of buildings in Indonesia must be concerned with earthquake loads. Installing shear walls in the building structure as the Special Moment Frame Dual System is one of a solution to withstand earthquake loads. However, the location of shear walls must be considered, especially in buildings with horizontal irregularities. This study aims to determine the optimum location of the shear walls in a 10-storey building that has U-configuration with dynamic earthquake loads. This research is a numerical simulation ran by modelling the structure with software. To know the effect of the shear wall’s location on a building, several variations of the shear wall configuration with different positions have been conducted. It can be seen the lateral displacement of each floor and the shear force are the response structure to withstand the dynamic earthquake loads. Shear walls that are located close to the center of mass of the building are the optimum variation because the position of the shear wall is the closest to the core area of the building, which is the rotational axis of the building.