Department of Engineering - Annual Report 1999/2000

Structures

Steel and Composite Steel-,Concrete Structures
Reinforced Concrete Structures
Lateral Stability of Precast Concrete Beams
Polyester and Aramid Fibre Properties
Non-metallic Reinforcement for Concrete
Application of Geometric Algebra to Beam Stability
Design Philosophy for Concrete Slabs
Partially Bonded Non-metallic Prestressing Tendons
Strengthening and Repair of Existing Strictures
Joining of Advanced Composite Pipelines
Bridge Engineering
Deployable Structures
Analysis of Symmetric Structures
Dynamics of Nonlinear Elastic Systems
Long Span Bridges Aeroelasticity
Human-Structure Interaction on Pedestrian Bridges
Shell Structures
Pipeline Problems
Structural Mechanics in Molecular Biology
History of Construction
Curriculum Development

References

Steel and Composite Steel-Concrete Structures

An investigation into the use of different constructional materials in large-span shallow domes of reticulated, composite construction has been almost completed. Numerical models for shear-weak members have been derived, which include the de-stabilising effects of significant axial force. These models are being incorporated in a Dynamic Relaxation routine, which has been successfully compared with the results of tests on a 1 m span grid shell. The program is now being used to study shear-weak (in plane and out of plane) shallow domes with rectangular grids.

Reinforced Concrete Structures

Dr C.T. Morley 

Research has continued on simplified approaches to the analysis of structures made of materials such as concrete exhibiting marked strain-softening after little or no plastic flow^(H8). Progress is being made using the Galerkin method. Tests have been carried out on heavily-reinforced slabs with a single developing yield-line of limited rotation capacity, for comparison with the theoretical approach^(H7).

Research work continues on compressive membrane-action in reinforced concrete slabs, and on the importance of proper modelling of bond in non-linear finite element analysis of reinforced concrete. A study is beginning of the possible advantages of enforcing carbonation of plain concrete. 

Lateral Stability of Precast Concrete Beams

Work has continued on the stability of heavy concrete beams, with particular reference to the problems induced when the beams are being lifted^(H43). Unlike steel beams, which buckle in a lateral-torsional mode, concrete beams have higher torsional stiffness and buckle by minor-axis bending combined with a rigid-body rotation - a toppling mode. Theoretical results have shown that any increase in beam lengths beyond those currently in use will make buckling a critical design parameter.

Polyester and Aramid Fibre Properties

The long-term mechanical properties of polyester and aramid fibres are being studied, with a view to drawing up safe levels of tension load for long-term structural applications. In the case of polyester, the uses are normally as soil-reinforcement; while for aramids, the normal uses would be as prestressing tendons. In both cases, a proper understanding of the stress-rupture, creep and relaxation properties can have a significant impact on the economics of using such materials.

Non-metallic Reinforcement for Concrete

Although the normal use of non-metallic systems in concrete will be as prestressing tendons, such systems can also be used to reinforce against shear, and to provide restraint against compressive failure. Both end-uses require modification of the conventional wisdom about structural behaviour.

In the case of shear reinforcement, yielding of the reinforcing links can no longer be relied on, which means that the usual plasticity theorems no longer hold^(H19). This, in turn, means that an explicit relationship is required between the shear deformation and the forces in the links in which the bond behaviour is critical, since this controls the way in which the elements move relative to one another. A model of the equilibrium of the "tooth" of concrete between shear cracks is being developed {Stratford, T.J., PhD dissertation, see Section IV].

The ability of systems based on fibres to provide restraint against compressive failure is well-known; but it has been ignored in the current design philosophy that "under-reinforced" failure is desirable, so that the tendon fails before the concrete. If beams are to be built with non-metallic tendons, and those tendons are brittle, that would imply that "over-reinforced" failure, where the concrete crushes before the tendon snaps, is desirable. Thus, a significant increase in structural ductility can be achieved by providing hoop reinforcement in the compression zone of beams. The consequence is not to increase the overall strength of beams significantly, but rather to enhance the strain capacity, so that substantial amounts of energy are dissipated within the concrete when it crushes.

Work has continued on the behaviour of anchorage systems for prestressed concrete, so that we now have a full understanding of the friction, abrasion and stress-concentration behaviour in barrel-and-spike terminations^(H2).

A review of European applications for composites in concrete has been undertaken. It is clear that the development of such systems now relies on economic and commercial developments, rather than technical ones^(H3).

Application of Geometric Algebra to Beam Stability

A study has been carried out into the use of geometric algebra to represent the orientation of a beam element during the pre- and post-buckling deformations of a beam. This allows a consistent formulation of the equations, both as the load increases and at different positions along the beam. In the course of this work a new formulation for interpolation of rotations in finite-difference formulations has been developed^(H6).

Design Philosophy for Concrete Slabs

A review of various design strategies for concrete slabs has been undertaken, with particular reference to designs carried out in the 1960s using lower-bound plasticity techniques: these are now being checked using finite element analysis. It has been shown that too much reliance on modern methods of elastic analysis can lead to reinforced-concrete structures being condemned or strengthened unnecessarily^(H4). 

Partially Bonded Non-metallic Prestressing Tendons

The behaviour of concrete beams prestressed with partially bonded non-metallic tendons has been considered. The work has demonstrated the principle that it is possible to achieve both high strength (normally associated with fully-bonded systems), and high rotation capacity (normally associated with unbonded systems), by judiciously debonding the tendons. In addition, the study has given insight into the appropriate design methodology and the optimum partial bond parameters^(H26,H27). Extensions to this project have included a further investigation of the bond mechanism between the tendons and the concrete. A particular focus has been the apparent locking behaviour of spiral-wound aramid fibre reinforced plastic reinforcement.

Strengthening and Repair of Existing Structures

Dr J.M. Lees 

Research is being carried out in the field of strengthening and repair of structures. A particular focus has been the use of advanced composite materials as a means of increasing the shear and/or flexural capacity of existing structures.

An investigation of the shear enhancement of concrete using external carbon fibre reinforced plastic (CFRP) straps is continuing. The CFRP straps are prestressed and will potentially compensate for an existing structure which otherwise has insufficient shear reinforcement. The project, which is run in collaboration with the Swiss Federal Laboratories for Materials Testing and Research (EMPA), has considered the key design parameters of this innovative system. A significant increase in the ultimate capacity of experimental beam specimens has been achieved and the considerable promise of the system established^(H29). Work continues on the influence of the strap stiffness, spacing and initial level of prestress on the performance of the strengthened concrete members^(H28). A non-linear finite element analysis of this complex problem has been initiated.

Research which studies flexural strengthening of beams using either tensioned or non-tensioned CFRP laminates is also being carried out. Two particular applications are under consideration: the use of stressed laminates for the strengthening of cast iron bridges, and the performance of non-tensioned CFRP laminates to improve the flexural capacity of reinforced concrete beams. A specific area of interest is the behaviour at the interfaces between the laminate, the adhesive and the substrate.

Joining of Advanced Composite Pipelines

Although advanced composites have been used extensively in the aerospace and manufacturing industries, to date their potential has not been fully exploited in infrastructure applications. One contributing factor is the difficulty associated with the joining of these novel materials. Research that seeks to address this important problem is currently in progress.

Funding for two separate EPSRC projects has been secured for research relating to high-performance connection systems for advanced composite pipelines. The first project, in association with Rolatube Ltd., considers the design of a longitudinal seam in bistable composite tubes. The second project investigates the joining of filament-wound pipe sections using combined mechanical/bonded connections. The work will investigate these innovative systems with the aim of achieving an optimum joint configuration. 

Bridge Engineering

Research on bridge assessment is continuing, with emphasis on the development and evaluation of collapse-analysis methods for assessing the strength and safety of various types of concrete bridge under different load configurations. The COBRAS generalised yield-line collapse-analysis program, developed within the group and released through the University's technology transfer company, C.U.T.S., has been adopted widely both in the UK and overseas. This program is believed to be the world's most advanced commercially available yield-line program. Very substantial savings for bridge owners have resulted from the more realistic predictions of strength that have been obtained by use of this approach. Research to develop a computerized method for interactively drawing failure mechanisms and automatically deriving compatible failure mode geometries is continuing, using various 3D computer-graphics techniques. 

The ongoing program of tests on concrete bridge models to examine the effects of bridge geometry, reinforcement and live loading on the modes of failure have continued. In particular the effects of high skew, bond and reinforcement percentage are being examined. A separate study of failure modes in cantilevered bridge deck slabs is also under way. 

A research contract, funded by the Highways Agency, aimed at examining the whole-life performance of concrete bridges and, in particular, developing practical deterioration models for use in the assessment of concrete bridge performance has now been completed^(H38). Leading on from this a new project examining uncertainty in inspection and testing (NDT) of bridges, also funded by the Highways Agency and an industrial sponsor, has commenced. 

A novel software package combining yield-line methods of structural assessment with reliability analysis has been developed; it allows variability in the key parameters of strength and loading to be taken into account in a structural assessment. This provides a quantitative measure of the relative failure probabilities of structures, and can be used for ranking existing bridges in order to identify those most in need of strengthening or replacement. 

There is ongoing research aimed at investigating the suitability and limits of applicability of reliability analysis methods in bridge engineering and bridge management^(H17,H36). 

An investigation into the use of non-destructive testing techniques for determining the location and degree of corrosion in the reinforcing bars of concrete structures has been completed and has set the foundations for further developments in this area. 

A number of very successful one-day courses for bridge engineers on the application of yield-line analysis and the COBRAS program have been held in Cambridge, Wales and Scotland. 

Deployable Structures

Several advances have been made in deployable reflector structures. A new, improved configuration of the spring-back reflector - originally developed by the Hughes Corporation- has been found. With some subtle design changes, the deployed stiffness of this structure has been increased twenty-fold with only 16% increase in mass, thus leading to an eight-fold increase in the fundamental frequency of vibration^(H44). New designs of umbrella-type reflectors have been identified, in collaboration with ELTA, Israel^(H24). On-going research on rib-tensioned surface reflectors, on behalf of the European Space Agency, has continued.

A research project, funded by EPSRC, is looking into self-actuated bi-stable structures. Simple examples of such structures can be found, for example, in many electrical switches and toys. This project aims to extend the bi-stable composite tubular shells pioneered by Rolatube Ltd, which are in equilibrium both extended and rolled-up. Several new bi-stable shell structures have been identified. Earlier work on bi-stable composite tubes has been published^(H20,H21).

Work on gravity compensation of deployable structures is nearing completion; interim results have been published^(H9).

A theoretical/computational framework for the analysis of special configurations of kinematic bifurcation in deployable structures consisting of pin-jointed bars has been developed and applied to the simulation of simple models of solar sail deployment^(H23). 

A study, funded by the European Commission Mobility Programme, has led to the discovery of a previously unknown kind of instability in mechanical systems with unilateral constraints. This instability manifests itself as the sudden loss of equilibrium leading to a jump of the system, and is associated with the change of state of one or more unilateral constraints that are weakly active, i.e. in contact but with zero reaction. A theory has been proposed for this type of instability^(H39) and has been able to produce correct simulations of the previously unexplained, anomalous behaviour of a solid-surface deployable reflector^(H40). 

Studies of instabilities in thin membrane structures are under way. High pressure atmospheric balloons, which have a characteristic lobed construction, are prone to a kind of global instability that leads to a part of the balloon surface remaining inside its envelope. A fundamental study of this instability was presented at the AIAA SDM Conference in Atlanta^(H30) only months before a major failure in the NASA Long Duration Flight Experiment was caused by this instability.

Studies of the dynamic deployment of structures containing tape springs, both longitudinally straight, as in standard steel tape measures, and curved have been published^(H42). 

New concepts for structures for space-based deployable radar are being developed, in collaboration with DERA, Farnborough, and ASTRIUM.

The proceedings of the first conference specifically devoted to deployable structures, held in Cambridge in September 1998, have been published^(H37). The opening lecture, by Professor Calladine^(H5), discussed the links between deployable structures and biological structures; this is an area of growing interest.

Analysis of Symmetric Structures

Work is continuing both on the basic theoretical development of the use of symmetry in structural analysis, and also on the practical applications, in particular using symmetry to aid the development of new deployable structures. New work has started this year on the analysis of repetitive structures. 

An introductory paper on symmetry and structural analysis was published this year in the Millennium Issue of the Transactions of the Royal Society^(H13). Papers have also been published on the application of group theory to equilibrium and compatibility relationships^(H22), the development of a symmetry-adapted Maxwell's rule^(H10), and the application of a recently developed method for detecting finite mechanisms^(H12). 

Dynamics of Nonlinear Elastic Systems

Research is being conducted into the dynamical behaviour of nonlinear elastic systems, focusing on the application of dynamical systems theory. In collaboration with Dr J Lasenby, the use of Clifford Algebra has been developed as the appropriate mathematical framework in which to construct a large-rotation rod theory suitable for finite-element implementation. Work has also been undertaken on the development of dimension-reduction algorithms for extracting low-dimensional dynamic models from massive numerical simulations, by the application of techniques of inertial manifold approximation. 

Long Span Bridges Aeroelasticity

Work is in progress assessing the applicability of computational fluid dynamics (CFD) to the design of long-span bridges. Using in-house finite volume and discrete vortex codes capable of fully-coupled fluid-structure interaction analysis, the various aeroelastic instabilities such as flutter and vortex-induced oscillations can be modelled in the time domain, providing detailed insights to supplement wind-tunnel tests and simpler mathematical descriptions^(H35). 

Human-Structure Interaction on Pedestrian Bridges

 Experimental and theoretical investigations have been undertaken into the complex biofeedback interactions that occur when people walk on moving and spring-supported surfaces. The work was stimulated by events on London's Millennium Bridge, and conducted in collaboration with Dr J Lasenby of the Signal Processing Group, whose motion-capture equipment allows detailed inspection of the human kinematics

Shell Structures

Experimental and theoretical work continues on the buckling performance of thin-walled cylindrical shells under predominantly axial compressive loading. A computational study of the consequences of geometrical imperfections on account of welding procedures has been completed^(H18). Experiments on a 0.25 mm thick mylar shell of diameter 0.9 m and height 0.7 m have revealed some strikingly paradoxical behaviour. Thus, a local "uplift" imperfection at the base may induce a dimple in the shell under zero axial load. When the load is increased the dimple tends to enlarge and move up the shell, until catastrophic buckling occurs when the dimple reaches a critical size. It has also been found that a "frictional" connection between the shell wall and the end discs significantly improves the buckling performance^(H25). An experimental study of self-weight buckling of small-scale open-topped cylindrical shells has shown that the vertical self-weight stress at the base at buckling is proportional to the thickness of the shell raised to the power of 1.5, other things being equal. This phenomenon has been mimicked by a non-linear analysis using ABAQUS software^(H31). These two pieces of work taken together have led to a novel and radical explanation of the long-time puzzling empirical buckling behaviour of thin-walled cylindrical shells under axial compression.

Pipeline Problems

Laboratory-scale modelling, associated computing and dimensional analysis have elucidated the problem of lateral thermal buckling of a long elastic pipeline resting on a frictional sea-bed. As temperature rises a localised buckle forms in a region of geometrical imperfection; and it grows in amplitude and wavelength as temperature rises further. But then the first buckle stops growing, and growth is transferred to adjacent buckles as temperature continues to rise. In this way a region of "extinct" buckles is left, flanked at either end by zones of growing buckles. The amplitude and wavelength of the extinct buckles depend in a very simple way on the elastic bending stiffness of the pipeline and the longitudinal and transverse frictional constants. So far we have failed to find a convincing and simple explanation for these surprising (and useful) observations^(H34). [See also section I - Petroleum Engineering]. 

Structural Mechanics in Molecular Biology

The structure of a trans-membrane protein, TolC, has recently been determined by Dr Ben Luisi's group in the Department of Biochemistry. The central portion of TolC is a simple cylindrical tube made from twelve a-helices stacked side-by-side. Now when two a-helices stack side-by-side they normally form a twisted "coiled coil"; and in order to stack in the manner of TolC, the a-helices must be untwisted. We have discovered, by studying the detailed geometry, and in particular the pattern of inter-residue distances, that the untwisting is achieved in nature by a particular pattern of large and small hydrophobic residues on the a-helix surface. It may be possible to design a-helices that assemble in a similar way to form "nano-tubes"; which could have widespread biotechnical implications.

History of Construction

It is widely agreed in the engineering profession and in academia that it is desirable for students to be acquainted with the history of their disciplines. Emeritus Professor Heyman continues to write books and articles^(H15,H16) about the history of the development of structural thinking and practice. His motive is "not to rake over the past, but to illuminate the activity of the present-day structural engineer, and to show how a store of scientific information can be used creatively in design". One cannot help thinking that if more engineers were familiar with such expositions of structural wisdom, there would be fewer structural disasters today.

Curriculum Development 

A new third-year project has been developed on the use of computers in the analysis and design of multi-bay, multi-storey building frames. The students use several standard commercial software packages. The last exercise concerns Professor Heyman's design for our own Inglis B building. Elastic analysis suggests that the design is unsafe (which has an electrifying effect on the students, currently in the building). But the formation of plastic hinges (which may be inserted in the final software package) brings the building into safe behaviour^(H32). Often in the general analysis of structures the equations of equilibrium furnish linear algebraic equations linking the (internal) bar tensions and the (external) forces. But the corresponding matrices are in general not square. Gauss-Jordan elimination of the equilibrium matrix reveals the number and characteristics of any states of self-stress, and also shows if the assembly is indeed a (kinematically indeterminate) mechanism rather than a rigid structure; and all of this is highly relevant to structural engineering. For several years now our third-year students have been introduced in lectures to the very close and complete relationship between the structural mechanics of simple bar-and-joint assemblies and elementary linear algebra^(H14).

H1. Barker, R.J.P., Guest, S.D. Inflatable triangulated cylinders. In: IUTAM-IASS Symposium on Deployable Structures, Theory and Applications, Proceedings, IUTAM Symposium, Cambridge (September 1998); Edited by S. Pellegrino, S.D. Guest, 17-26. Solid Mechanics and Its Applications 80 (Kluwer Academic Publishers, 2000). ISBN 079236516X.

H2. Brown, I.F., Burgoyne, C.J. The friction and wear of Kevlar 49 sliding against aluminium at low velocity under high contact pressure. Wear, 236, (1-2), 315-327 (December 1999).

H3. Burgoyne, C.J. Advanced composites in civil engineering in Europe. Structural Engineering International, 9, (4), 267-273 (November 1999).

H4. Burgoyne, C.J. Design or analysis - elastic or plastic. Henderson Colloquium - Making the Most of our Structures, Cambridge (July 2000).

H5. CALLADINE, C.R. Deployable structures: what can we learn from biological structures? In: IUTAM-IASS Symposium on Deployable Structures, Theory and Applications, Proceedings, IUTAM Symposium, Cambridge (September 1998); Edited by S. Pellegrino, S.D. Guest, 63-76. Solid Mechanics and Its Applications 80 (Kluwer Academic Publishers, 2000). ISBN 079236516X.

H6. Clements, J.M., Lasenby, J., Burgoyne, C.J. Interpolation of rotations in finite difference schemes using geometric algebra. Applied Clifford Algebras in Computer Science and Engineering (ACACSE 99), Ixtapa, Mexico (June 1999).

H7. Denton, S.R., Morley, C.T. Accounting for limited ductility in concrete structures. fib Symposium, Structural Concrete - the Bridge Between People, Prague, Czech Republic (October 1999).

H8. Denton, S.R., Morley, C.T. Limited analysis and strain-softening structures. International Journal of Mechanical Sciences, 42, (3), 503-522 (March 2000).

H9. Fischer, A., Pellegrino, S. Interaction between gravity compensation suspension system and deployable structure. Journal of Spacecraft and Rockets (AIAA), 37, (1), 93-99 (January-February 2000).

H10. Fowler, P.W., Guest, S.D. A symmetry extension of Maxwell's rule for rigidity of frames. International Journal of Solids and Structures, 37, (12), 1793-1804 (March 2000).

H11. Galletly, D.A., Guest, S.D. Equilibrium and stability analysis of bistable composite slit tubes. IASS-IACM 2000, 4th International Colloquium on Computation of Shell and Spatial Structures, Chania, Crete, Greece (June 2000).

H12. Guest, S.D. Mechanisms of the icosahedral compound of ten tetrahedra. 4th Geometry Festival, Eötvös University, Budapest, Hungary (November/December 1999). Published in: Periodica Mathematica Hungarica, 39, (1-3), 213-223 (1999).

H13. Guest, S.D. Tensegrities and rotating rings of tetrahedra: a symmetry viewpoint of structural mechanics. Philosophical Transactions of the Royal Society of London Series A: Mathematical, Physical and Engineering Sciences (Millennium Issue), 358, (1765), 229-243 (January 2000).

H14. Guest, S.D., Calladine, C.R. Matrices in the teaching of statically indeterminate structures. Proceedings, Conference on Civil and Structural Engineering Education in the 21st Century, Southampton; Edited by H.G. Allen, 285-296 (April 2000). ISBN 0854327177.

H15. Heyman, J. Palladio's wooden bridges. Architectural Research Quarterly, 4, (1), 81-85 (2000).

H16. Heyman, J. The Science of Structural Engineering. (Imperial College Press, 1999). ISBN 1-86094-189-3.

H17. Hogg, V., Middleton, C.R. Effects of truncation on reliability analysis. Proceedings, ICASP 8 Conference, Applications of Statistics and Probability: Civil Engineering Reliability and Risk Analysis, Sydney, Australia (December 1999); Edited by R.E. Melchers, M.G. Stewart, 2, 1087-1094 (Balkema, 2000). ISBN 90 5809 086 8.

H18. Holst, J.M.F.G., Rotter, J.M., Calladine, C.R. Imperfections and buckling in cylindrical shells with consistent residual stresses. Journal of Constructional Steel Research, 54, (2), 265-282 (May 2000).

H19. Ibell, T.J., Burgoyne, C.J. Use of fibre-reinforced plastics versus steel for shear reinforcement of concrete. ACI Structural Journal, 96, (6), 997-1002 (November-December 1999).

H20. Iqbal, K., Pellegrino, S. Bi-stable composite shells. Proceedings, 41st AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, Atlanta, GA, USA, AIAA paper 2000-1385 (April 2000).

H21. Iqbal, K., Pellegrino, S., Daton-Lovett, A. Bi-stable composite slit tubes. In: IUTAM-IASS Symposium on Deployable Structures, Theory and Applications, Proceedings, IUTAM Symposium, Cambridge (September 1998); Edited by S. Pellegrino, S.D. Guest, 153-162. Solid Mechanics and Its Applications 80 (Kluwer Academic Publishers, 2000). ISBN 079236516X.

H22. Kangwai, R.D., Guest, S.D. Symmetry-adapted equilibrium matrices. International Journal of Solids and Structures, 37, (11), 1525-1548 (March 2000).

H23. Kumar, P., Pellegrino, S. Kinematic bifurcations in the simulation of deployable structures. IASS-IACM 2000, 4th International Colloquium on Computation of Shell and Spatial Structures, Chania, Crete, Greece (June 2000).

H24. Lai, C-Y., Pellegrino, S. Feasibility study of a deployable mesh reflector. Cambridge University Engineering Department Technical Report CUED/D-STRUCT/TR.186 (2000).

H25. Lancaster, E.R., Calladine, C.R., Palmer, S.C. Paradoxical buckling behaviour of a thin cylindrical shell under axial compression. International Journal of Mechanical Sciences, 42, (5), 843-865 (May 2000).

H26. Lees, J.M., Burgoyne, C.J. Analysis of concrete beams with partially-bonded composite reinforcement. ACI Structural Journal, 97, (2), 252-258 (March-April 2000).

H27. Lees, J.M., Burgoyne, C.J. Design guidelines for concrete beams prestressed with partially-bonded FRP tendons. 4th International Symposium on Fiber Reinforced Polymer Reinforcement for Reinforced Concrete Structures (FRPRCS-4), Baltimore, MD, USA (Ocotber/November 1999); Edited by C.W. Dolan, S.H. Rizkalla, A. Nanni, 807-816. ACI SP-188 (American Concrete Institute, 1999).

H28. Lees, J.M., Winistoerfer, A.U., Meier, U. Behaviour of concrete beams confined with prestressed carbon fiber reinforced plastic straps. Proceedings, 3rd International Conference on Advanced Composite Materials in Bridges and Structures (ACMBS-III), Ottowa, Canada (August 2000); Edited by J.L. Humar, A.G. Razaqpur, 185-192 (Canadian Society for Civil Engineers, 2000). ISBN 0-7709-0447-5.

H29. Lees, J.M., Winistoerfer, A.U., Meier, U. Non-laminated pin-loaded CFRP straps for the shear enhancement of concrete. 4th International Symposium on Fiber Reinforced Polymer Reinforcement for Reinforced Concrete Structures (FRPRCS-4), Baltimore, MD, USA (October/November 1999); Edited by C.W. Dolan, S.H. Rizkalla, A. Nanni, 985-994. ACI SP-188 (American Concrete Institute, 1999).

H30. Lennon, B.A., Pellegrino, S. Stability of lobed inflatable structures. Proceedings, 41st AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, Atlanta, GA, USA, AIAA paper 2000-1728 (April 2000).

H31. Mandal, P., Calladine, C.R. Buckling of thin cylindrical shells under axial compression. International Journal of Solids and Structures, 37, (33), 4509-4525 (August 2000).

H32. McRobie, F.A. Teaching the appropriate use of structural analysis software. Proceedings, Conference on Civil and Structural Engineering Education in the 21st Century, Southampton; Edited by H.G. Allen, 2, 613-625 (April 2000). ISBN 0854327177.

H33. McROBIE, F.A., LASENBY, J. The kinematics of large rotations using Clifford algebra. In: IUTAM-IASS Symposium on Deployable Structures, Theory and Applications, Proceedings, IUTAM Symposium, Cambridge (September 1998); Edited by S. Pellegrino, S.D. Guest, 271-280. Solid Mechanics and Its Applications 80 (Kluwer Academic Publishers, 2000). ISBN 079236516X.

H34. Miles, D.J., Calladine, C.R. Lateral thermal buckling of pipelines on the sea bed. Transactions of the ASME, Journal of Applied Mechanics, 66, (4), 891-897 (December 1999).

H35. Morgenthal, G., McRobie, F.A. A comparative study of numerical methods for fluid-structure interaction analysis in long-span bridge design. 3rd International Symposium on Computational Wind Engineering, Birmingham (September 2000).

H36. Palmer, A.C., Middleton, C.R., Hogg, V. The tail sensitivity problem, proof testing, and structural reliability theory. Structural Integrity in the 21st Century, Proceedings, 5th International Conference on Engineering Structural Integrity Assessment, Cambridge (September 2000); Edited by J.H. Edwards et al, 435-442 (EMAS Publishing, 2000).

H37. Pellegrino, S., Guest, S.D. (Editors) IUTAM-IASS Symposium on Deployable Structures: Theory and Applications, Proceedings, IUTAM Symposium, Cambridge (September 1998). Solid Mechanics and Its Applications 80 (Kluwer Academic Publishers, 2000). ISBN 079236516X.

H38. Roberts, M.B., Atkins, C., Hogg, V., Middleton, C.R. A proposed empirical corrosion model for reinforced concrete. Proceedings of the Institution of Civil Engineers, Structures and Buildings, 140, (1), 1-11 (February 2000).

H39. Schulz, M., Pellegrino, S. Equilibrium paths of mechanical systems with unilateral constraints, part I: theory. Proceeding of the Royal Society of London Series A: Mathematical, Physical and Engineering Sciences, 456, (2001), 2223-2242 (September 2000).

H40. Schulz, M., Pellegrino, S. Equilibrium paths of mechanical systems with unilateral constraints, part II: deployable reflector. Proceeding of the Royal Society of London Series A: Mathematical, Physical and Engineering Sciences, 456, (2001), 2243-2262 (September 2000).

H41. Sebastian, W.E., McConnel, R.E. Nonlinear FE analysis of steel-concrete composite structures. Journal of Structural Engineering (ASCE), 126, (6), 662-674 (June 2000).

H42. Seffen, K.A., Pellegrino, S., Parks, G.T. Deployment of a panel by tape-spring hinges. In: IUTAM-IASS Symposium on Deployable Structures, Theory and Applications, Proceedings, IUTAM Symposium, Cambridge (September 1998); Edited by S. Pellegrino, S.D. Guest, 355-364. Solid Mechanics and Its Applications 80 (Kluwer Academic Publishers, 2000). ISBN 079236516X.

H43. Stratford, T.J., Burgoyne, C.J. The toppling of hanging beams. International Journal of Solids and Structures, 37, (26), 3569-3589 (June 2000).

H44. Tan, L.T., Pellegrino, S. Stiffening method for "spring-back" reflections. IASS-IACM 2000, 4th International Colloquium on Computation of Shell and Spatial Structures, Chania, Crete, Greece (June 2000).

H45. YOU, Z. A new approach to design of retractable roofs. In: IUTAM-IASS Symposium on Deployable Structures, Theory and Applications, Proceedings, IUTAM Symposium, Cambridge (September 1998); Edited by S. Pellegrino, S.D. Guest, 477-483. Solid Mechanics and Its Applications 80 (Kluwer Academic Publishers, 2000). ISBN 079236516X.

[Table of Contents]

Last modified: July 2000