Study On Control Techniques Of Concrete Construction Formwork Structure System

Concrete structures are the most common structure form in modern civil engineering; Formworks have to be used to perform it. The cost of formwork engineering may account for an important part of total construction cost. Safety accidents due to formwork collapse also form a big share of all construction accidents. With the widely use of large span & high clearance concrete structure, these problems become more and more severity.In domestic construction market, fastener-style steel pipe falsework have been widely used. But the frequent collapse accidents are also a boring problem. This is generally owed to the lack of design and management technique. It was until 2001, the first national code about scaffold was issued. But the provisions about falsework in the code are very few, this lead to chaos of configuration. Since the difference in configuration of domestic and abroad code, the key provisions copied from abroad code about falsework's calculation are regard as unsafe by many experts. All these have to be solved urgently.Based on other's works about scaffold experiments and calculation models, theauthor performed following works through analysis, calculation, and investigation:1 Through 3-dimension FEM simulation analysis of scaffold experiments, theauthor extracted a parameter from the results: calculation length modifyingcoefficient, which is independent of scaffold's configuration and underpinningconditions; and set up a calculation method—the calculation length modifyingcoefficient method for ideal frame calculation model. Using this method, theauthor recalculated the calculation lengths coefficient table (code table 5.3.3 ) withsame configuration conditions. Same results as code (which were gotten from summary of experimental results) are gotten. This proved the validity of the method author suggested.2 Using this method to falsework analysis, following work are performed:? The influence of configuration condition to stability bearing capacity is studied; such as step length, span, bridging in horizontal planes, bridging in uprightness planes, the floor members, the length of upright bars extruding from top horizontal bars.? The calculation method prescribed in code is analyzed; it is founded that it may be unsafe in certain circumstance. According the analysis results, the author suggested a group calculation length coefficient for the design of falsework.3 An investigation was carried out about falsework configuration in situ. A method for determining the safe span of upright bars in real management condition is suggested. Using this method, the span of upright bars is analyzed for different heights of falsework under commom loads.4 Some typical falsework collapse accidents happened in recent years are Summarized and analyzed, measures which should been taken to prevent them are suggested.5 The factors which influence falsework' safety are analyzed and an evaluation method is suggested.6 The work performed in cost and resource management:① Using fuzzy clustering method, a method for cost or resources predication issuggested.② Cost plan is also studied using interval number concept. ③ Under multi-projects construction, a resource allocation method is suggested forthe problem that resources supply changes with time. ? Under the consideration of resource variation cost, an optimum method forproject network is suggested.