Reliability assessment of steel scaffold shoring structures for concrete formwork

Abstract Many failures of concrete structures during construction are traceable to the collapse of formwork shoring systems. A reliability analysis for typical steel scaffold shoring structures is presented herein utilizing recent survey data on geometric and mechanical properties of steel scaffold members, and a second-order inelastic structural analysis model. Published shore load surveys were analyzed to develop the probabilistic models for loads acting on scaffolds during concrete placement. The paper investigates the mode of failure, the effects of different random variables on the variability of structural strength, and the reliability of the analyzed scaffold structures. The reliability framework can be used to improve the current working load limit basis for the design of steel scaffold structures and make scaffold design risk-consistent.

[1]  D. R. Huston,et al.  INVESTIGATING THE ADEQUACY OF VERTICAL DESIGN LOADS FOR SHORING , 1998 .

[2]  S. L. Chan,et al.  Advanced Analysis of Imperfect Portal Frames with Semirigid Base Connections , 2005 .

[3]  Kim J.R. Rasmussen,et al.  Investigation of geometric imperfections and joint stiffness of support scaffold systems , 2011 .

[4]  Bruce R. Ellingwood.  DESIGN AND CONSTRUCTION ERROR EFFECTS ON STRUCTURAL RELIABILITY , 1987 .

[5]  W. F. Chen,et al.  High clearance scaffold systems during construction —I. Structural modelling and modes of failure , 1996 .

[6]  Zhihua Chen,et al.  Experimental and analytical studies on the stability of structural steel tube and coupler scaffolds without X-bracing , 2010 .

[7]  Kim J.R. Rasmussen,et al.  Structural modelling of support scaffold systems , 2011 .

[8]  Mark D. Bowman,et al.  Construction Load Analysis for Concrete Structures , 1985 .

[9]  D. S. Gromala,et al.  Calculating apparent reliability of wood scaffold planks , 1984 .

[10]  I. Puente,et al.  Shore–slab interaction in multistory reinforced concrete buildings during construction: An experimental approach , 2007 .

[11]  Wai-Fah Chen,et al.  Improved Analysis of Shore-Slab Interaction , 1992 .

[12]  Steve Ferguson.  Formwork shore design loads : an evaluation of current practice , 2001 .

[13]  Fabian C. Hadipriono,et al.  Causes of falsework collapses during construction , 1987 .

[14]  Bruce R. Ellingwood,et al.  Probability Based Load Criteria: Load Factors and Load Combinations , 1982 .

[15]  Andrzej S. Nowak.  Effect of Human Error on Structural Safety , 1979 .

[16]  Kwok-Fai Chung,et al.  Structural instability of multi-storey door-type modular steel scaffolds , 2004 .

[17]  S. L. Chan,et al.  Effects of geometrical shape and incremental loads on scaffold systems , 2007 .

[18]  Robert E. Melchers,et al.  Structural Reliability: Analysis and Prediction , 1987 .

[19]  W. F. Chen,et al.  Stability analysis of semirigid steel scaffolding , 1995 .

[20]  T. Galambos,et al.  Properties of Steel for Use in LRFD , 1978 .

[21]  David V. Rosowsky,et al.  Observations from Shore Load Measurements during Concrete Construction , 1997 .

[22]  Kenneth L. Carper.  Structural Failures During Construction , 1987 .

[23]  Kim J.R. Rasmussen,et al.  Probabilistic study of the strength of steel scaffold systems , 2010 .

[24]  Paul Grundy,et al.  Construction Loads on Slabs with Shored Formwork in Multistory Buildings , 1963 .

[25]  Mark G. Stewart.  Structural reliability and error control in reinforced concrete design and construction , 1993 .

[26]  Mark G. Stewart,et al.  Human Error and Reliability of Multistory Reinforced-Concrete Building Construction , 2004 .

[27]  D. V. Rosowsky,et al.  Accounting for Human Error during Design and Construction , 1995 .

[28]  Liu Ke.  SAFETY ACCIDENT OF FORMWORK ENGINEERING AND ITS PREVENTION IN CHINA , 2008 .

[29]  Saeed Karshenas,et al.  Construction live loads on slab formworks before concrete placement , 1994 .

[30]  L. B. Weesner,et al.  Experimental and analytical capacity of frame scaffolding , 2001 .

[31]  Saeed Karshenas,et al.  ANALYSIS OF CONCRETE CONSTRUCTION LIVE LOADS ON NEWLY POURED SLABS , 1994 .

[32]  Jukka Ikäheimonen.  Construction loads on shores and stability of horizontal formworks , 1997 .

[33]  Mark G. Stewart,et al.  Structural Reliability of Multistory Buildings during Construction , 2002 .