Welcome
Digital library of construction informatics
and information technology in civil engineering and construction
 

Works 

Search Results

Facilitated by the SciX project

Hits 1 to 6 of 6

Al-Tabtabai H, Alex A P, James R

Slab formwork design using genetic algorithm

Abstract: A method to design cost-optimum slab formwork components is proposed in this paper. Genetic Algorithms (GAs), a technique based on the principles of natural selection and evolution, is applied to solve the optimisation problem. GAs search from a population of possible solutions limited by a set of constraints. The cost of form components and labor involved, were considered for the formulation of the objective function of the optimisation problem. The bending moment, shear, maximum deflection, imposed ACI code provisions, etc., were used as constraints for the optimisation problem. Application of GA to the formwork design problem provides optimum design parameters such as the optimum cross section for form members, optimum spacing of form members, etc., while minimising the total cost. Formwork made either from wood, wood-metal composite or metal alone can be designed using the proposed technique. The paper presents the case of general formwork design, however, the method as a whole readily applies to the design of formwok for elevated slabs and high rise concrete elements.

Keywords:

DOI:

Full text: content.pdf (84,716 bytes) (available to registered users only)

Series: w78:1999 (browse)
Cluster: papers of the same cluster (result of machine made clusters)
Class: class.economic (0.011489) class.analysis (0.007703) class.retrieve (0.007266)
Similar papers:
Sound: read aloud.

Permission to reproduce these papers has been graciously provided by the Research Press of the National Research Council of Canada. The support of the editors, particularly Dr. Dana Vanier, is gratefully appreciated.


Grabska E, Borkowski A

Generating floor layouts by means of composite representation

Abstract: The paper deals with the design of single-family houses. Within the framework of graph trans- formations we introduce the composite representation. It facilitates reasoning about design at two levels: the syntactic level and the semantic level. The design process includes the interaction of constraints and design context with the graph rules used to describe topological properties. Several examples demonstrate application of the developed software.

Keywords:

DOI:

Full text: content.pdf ( bytes) (available to registered users only)

Series: ecce:1997 (browse)
Cluster:
Class:
Similar papers:
Sound: N/A.


Kilar V, Krstulovič-Opara N

Seismic behavior of high-performance fiber reinforced composite frames

Abstract: The paper explores the possibilities to use a High-Performance Fiber Reinforced Concretes (HPFRCs) for design of seismic resistant cost-effective and durable buildings. Composite frame buildings are made through selective use of different HPFRCs: Slurry Infiltrated Mat Concrete (SIMCON), Slurry Infiltrated Fiber Concrete (SIFCON) and High Strength - Lightweight Aggregate Fiber Reinforced Concrete (HS-LWA FRC) which further minimizes dead and seismic loads. The first part of the paper briefly describes used HPFRCs and proposed composite building system consisted of composite columns, beams and specially designed fuses that connect the two. In the second part of the paper the results of the nonlinear static analysis of an isolated composite beam as well as of the nonlinear dynamic analysis of a whole four-story example composite building are presented. The response in terms of forcedisplacement relationships and rotational ductility factors as well as in terms of base shear, top displacements and global damage index histories is compared to the response of an identical classical four-story building made of reinforced concrete.

Keywords: fiber reinforced concrete, high performance fiber reinforced concrete, composite building structures, seismic behavior, frame structures, nonlinear analysis

DOI:

Full text: content.pdf (1,086,539 bytes) (available to registered users only)

Series: itaec:2003 (browse)
Cluster:
Class:
Similar papers:
Sound: N/A.


M. Y. Rafiq, C. Sui, D. J. Easterbrook, G. Bugmann

Generality of using correctors to predict the behaviour of masonry wall panels

Abstract: The highly composite and anisotropic nature of masonry, which is a result of the variation in the proper-ties of the masonry constituents, makes it very difficult to find an accurate material model to predict its behaviour satis-factorily. Current research by the authors has focused more closely on the behaviour of laterally loaded masonry wall panels using model updating techniques supported by artificial intelligence (AI) tools. They developed the concept of corrector factors which models the variation in the properties over the surface of masonry wall panels. This research resulted in methodologies, which enables designers to more confidently predict the behaviour of masonry wall panels subjected to lateral loading. The paper will demonstrate the generality of using these techniques to predict the behav-iour of laterally loaded masonry wall panels tested by various sources.

Keywords: corrector factors, evolutionary computation, cellular automata

DOI:

Full text: content.pdf (711,673 bytes) (available to registered users only)

Series: w78:2007 (browse)
Cluster:
Class:
Similar papers:
Sound: N/A.


Moller B, Hoffmann A, Kluger J

Assessment of critical load situations during the life cycle of concrete structures

Abstract: In dimensioning reinforced concrete structures in accordance with EC2, an alternative method of describing the system load-bearing behaviour is by nonlinear simulations over significant periods of the life cycle. The realistic reinforced concrete FE model presented here takes into account nonlinear material laws for concrete and steel, fracture behaviour and composite action as well as viscous behaviour (nonlinear creep and shrinkage). Considering the example of a reinforced concrete box-type folded plate structure, critical loading situations (especially high shear loads) were investigated which lead to system failure at different times in the life cycle of the structure. System load-bearing reserves are clearly indicated by resultant stress redistributions.

Keywords:

DOI:

Full text: content.pdf ( bytes) (available to registered users only)

Series: ecce:1997 (browse)
Cluster:
Class:
Similar papers:
Sound: N/A.


Suraj Ravindran, Prakash Kripakaran, Ian F. C. Smith

Evaluating reliability of multiple-model system identification

Abstract: This paper builds upon previous work by providing a statistical basis for multiple-model system identifica-tion. Multiple model system identification is useful because many models representing different sets of modeling as-sumptions may fit the measurements. The presence of errors in modeling and measurement increases the number of possible models. Modeling error depends on inaccuracies in (i) the numerical model, (ii) parameter values (constants) and (iii) boundary conditions. On-site measurement errors are dependent on the sensor type and installation condi-tions. Understanding errors is essential for generating the set of candidate models that predict measurement data. Pre-vious work assumed an upper bound for absolute values of composite errors. In this paper, both modeling and meas-urement errors are characterized as random variables that follow probability distributions. Given error distributions, a new method to evaluate the reliability of identification is proposed. The new method defines thresholds at each meas-urement location. The threshold value pairs at measurement locations are dependent on the required reliability, char-acteristics of sensors used and modeling errors. A model is classified as a candidate model if the difference between prediction and measurement at each location is between the designated threshold values. A timber beam simulation is used as example to illustrate the new methodology. Generation of candidate models using the new objective function is demonstrated. Results show that the proposed methodology allows engineers to statistically evaluate the performance of system identification.

Keywords: system identification, multiple models, error characterization, reliability, measurements, model predic-tion

DOI:

Full text: content.pdf (1,262,641 bytes) (available to registered users only)

Series: w78:2007 (browse)
Cluster:
Class:
Similar papers:
Sound: N/A.


No more hits.

 

hosted by University of Ljubljana



includes

W78




© itc.scix.net 2003
Home page of this database login Powered by SciX Open Publishing Services 1.002 February 16, 2003