Applied Mechanics and Materials Vols. 580-583

Abstract: Pile inserting and pulling activities may occur for many times in some wellsite in Offshore Oilfield, that resulted in serious stratum disturbance and complex strength change, it’s difficult to select appropriate jack-up drilling platform in the workover process latterly. By applying American Petroleum Institute <API RP 2A-WSD> norms, calculating the pile bearing capacity of two typical jackup, combing with the actual data of jackup emplaced, this paper analyzes and compares the suitability of various type of jackup in place in seriously disturbed wellsite by pile inserting and pulling, and then offers a proposal on how to select the appropriate jackup in such wellsite as a reference.

Abstract: Many researches have been conducted in past decades for promoting the application of steel fibre reinforced concrete (SFRC), either conventional or self-compacting. However, the differences of post-crack behaviour and the properties of these two types of concrete remains unclear. The objective of this paper is to analyse such differences in terms of flexural behaviour, fibre orientation and contribution as well as the fibre content. For that, an extensive experimental campaign was carried out. In total 3 mixes of self-compacting and 3 mixes with traditional concrete were produced with the nominal fibre contents of 30kg/m³, 45kg/m³ and 60kg/m³. In each series, specimens were produces and characterized by three point bending test (code EN 14651) and inductive test. The results illustrate how fibre orientation and distribution justify the differences in the mechanical behaviour of the materials and the scatter of the bending test results.

Abstract: Traditional pre-stress FRP sheet tension fixture must have the beam of the bridge slotted to reduce the cross-section of the beam. Besides, stress on the FRP sheet is irregular with local stress concentration. Its indirect load pre-stress, as well as quantitative criterion of pre-stress born by FRP sheet is not accurate. To solve the above problems, a newly-developed self-balanced type pre-stress FRP sheet tension fixture has been introduced. Such a tension fixture consists of welded steel frame, a mechanical jackscrew, a dynamometer and a strain gauge. It is able to give specified stress onto the FRP sheet accurately while not damaging the beam cross-section. At the same time, with the combination of ANASYS Workbench and UG8.0 Software, also states the simulation analysis of the new type tension fixture, including its stress under practical work and deformation state, which initially proves the scientific and economic usefulness of such tension fixtures.

Abstract: Fastener-style steel pipe formwork support is currently the most widely used form of template support during the domestic construction. At present, there are many models for the node connection pattern. This paper used ANSYS to build different connection pattern models of formwork support and draws the conclusion that the connection pattern of semi-rigid nodes is the most conform to the actual working conditions. This provide the basis for the theoretical research on fastener-style steel pipe formwork support.

Abstract: Setting bracing is conducive to stabilize formwork support in high-formwork system. ABAQUS was used to build the calculating model of high-formwork system to simulate and analyse lateral deformation of high-formwork in different column’s spacing of bridging. The results show, increasing column’s spacing of bridging can add the whole lateral displacement of high-formwork, but, it is not obvious. Increasing appropriately column’s spacing can save material during construction.

Abstract: Bridging play a important role in guarantee the stability of the high-formwork support system as a whole, its arrangement location will affect the force of the frame body. This paper used the finite element analysis method to compare the bridging arrangement location under the beam with the bridging under the board which was arranged according to certain modules. the results show, the arrangement spacing of the bridging under the beam is greater than the bridging under the board, but its frame body lateral migration is smaller, sharing part of the axial force of beam bottom rod at the same time, that means the bridging under the beam is more beneficial for the stability of high-formwork support system.

Abstract: ANSYS finite element analysis software is used to simulate the changes of maximum lateral displacement of the high-formwork support system in different sequences of pouring concrete. In the condition of loading which was applied from one side to the other side, the maximum lateral displacement of the frame had a sudden increase in each loading process. In the condition of loading which was applied symmetrically, the maximum lateral displacement of the high-formwork steadily rising nearly straight with the load applied. So the symmetrical pouring concrete ways is better for the whole stability of the high-formwork.

Abstract: Composite inorganic fiber spray technology was based on high-strength interfacial agent, then sprayed an appropriate mixed proportion of ultrafine diameter (D <4μm) composite inorganic fibers, adhesives, cement and other raw materials through a dedicated spray equipment on the building roof (ceiling) or flank, which formed a homogeneous, porous, durable and eco-friendly cover layer. The key technology is combined composite inorganic fiber sprays’ adhesive, mixing, porous, insulation and acoustic fireproof mechanism with three key technology working principles " high-strength interfacial agent sector coverage ", " composite inorganic fibers + adhesive multiple mixed spray " and " continuous overall seamless fireproof insulating layer ", to achieve integrate engineering effects of insulation, fastness, energy-efficient, sound-absorbing and homogeneous coverage. The new technology solves acoustic insulation problems of public buildings with fireproof requirements as: underground garage ceiling, elevator shafts and fire passage, etc.

Abstract: In this paper, we sorted soft foundation treatment technology by quantifying based on evaluation technique of life cycle environmental load and choose cement mixing pile which life-cycle environmental load is small and spiral pump pressure CFG pile which carrying capacity is high to integrate. It not only improved soil compaction effects, but also solved the problems of other technologies in the foundation process, such as low carrying capacity, reduced diameter, broken pile, virtual pile and so on. Besides, it has reduced the cost of the project and the application prospects are broad.

Abstract: Quality control in the rotary drilling cast-in-place pile construction is of great difficulty. Once a quality problem occurs, it would have an impact on the quality of the whole project. The text mainly analyzes the causes for the common problems in rotary drilling cast-in-place pile onstruction and gives some corresponding measures to solve them combined with engineering cases.