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The purpose of this paper is to put forward a nvew reconfigurable multi-mode walking-rolling robot based on the single-loop closed-chain four-bar mechanism, and the robot can be changed to different modes according to the terrain.

Based on the topological analysis, singularity analysis, feasibility analysis, gait analysis and the motion strategy based on motor time-sharing control, the paper theoretically verified that the robot can switch between the four motion modes.

The robot integrates four-bar walking, self-deforming and four-bar and six-bar rolling modes. A series of simulation and prototype experiment results are presented to verify the feasibility of multiple motion modes of the robot.

The work presented in this paper provides a good theoretical basis for further exploration of multiple mode mobile robots. It is an attempt to design the multi-mode mobile robot based on single loop kinematotropic mechanisms. It is also a kind of exploration of the new unknown movement law.

Hardened cement paste is a heterogeneous system resulting from the grouping of particles, films, microcrystals and other solid structural elements bounded in a porous mass. The cement paste microstructure must be understood firstly due to its influence on concrete properties. The behaviour of concrete greatly depends on the conformation of localised special structures rather than on general structures found in the mass cement paste. The objective of this paper was to study the cement paste microstructure, as a function of the water–cement ratio, in order to interpret the variations of the steel–mortar bond strength and the developing of the corrosion process in steel–mortar specimens kept in tap water and 3 percent sodium chloride solutions for 1 year. A description of the steel–mortar interface was also provided.

EZN‐UC corrosion resistant sheets supplied by NKK to Nissan. NKK has started commercial supply of the newly‐developed highly corrosion resistant Excel Zinc type N zinc‐nickel alloy electroplated steel sheets with a universal coat (EZN‐UC) to Nissan Motor Co Ltd.

The purpose of this paper is to present the results of experimental testing of steel rebars at elevated temperatures. Three types of bars available in the local market in Pakistan were used. These data are not available in Pakistan.

Three types of bars were used, which included cold-twisted ribbed (CTR), hot-rolled deformed (HRD) and thermo-mechanically treated (TMT) bars. The diameter of the bar of each type was 16 mm. The bars were heated in an electrical furnace at temperatures which were varied from 100°C to 900°C in increment of 100°C. Bars of each type were also tested at ambient temperature as control specimens. The change of strength, strain and modulus of elasticity of the bars at high temperatures were determined.

The mechanical properties of the bars were nearly unaffected by the temperatures up to 200°C. CTR bars did not show yield plateau and strain hardening both at ambient and high temperatures. The high temperature yield strength and elastic modulus for all the three types of bars were similar at all temperatures. The yield plateau of both the HRD and TMT bars disappeared at temperatures greater than 300°C. The ultimate strength at high temperature of the HRD and TMT bars was also similar. The behaviours of the HRD and TMT bars changed to brittle beyond 400°C as compared to their behaviours at ambient temperature. The CTR bars exhibited ductile characteristics at failure at all the exposure temperatures relative to their behaviour at ambient temperature.

The parameters of the paper included the rebar type and heating temperature and the effects of temperature on strength and stiffness properties of the steel bars.

Building fire incidents have increased in Pakistan. As reinforced concrete (RC) buildings exist in the country in significant numbers, the data related to elevated temperature properties of steel is required. These data are not available in Pakistan presently. The presented paper aims at providing this information for the design engineers to enable them to assess and increase fire resistance of RC structural members.

The presented paper is unique in its nature in that there is no published contribution to date, to the best of authors’ knowledge, which has been carried out to assess the temperature-dependent mechanical properties of steel reinforcing bars available in Pakistan.

To provide an insight in one relatively simple and efficient numerical model for analysing reinforced and prestressed concrete structures, and to raise a discussion leading to the creation of one universal and robust 3D algorithm.

A new numerical model for analysing reinforced and prestressed concrete structures is developed and main theoretical details are described to aid the understandings. The approach is clear, easily readable and the body of the text is divided into logical sections starting from theoretical explanations ending in the large number of different practical examples.

Provides information about developing new and relatively simple numerical model for analysing reinforced and prestressed concrete structures, indicating what can be improved. Recognises the lack of knowing real behaviour of 3D concrete and starts a discussion on it.

The knowledge of the 2D and especially 3D concrete behaviour is still poor and the concrete model developers use many simplifications. So, many new experiments should be performed and better numerical models should be developed. There is large area for researchers but having in mind that experiments are very expensive.

Obtained results of the 3D analysis of reinforced and prestressed concrete structures can stand as a benchmark for future researches in this field especially to the young researchers and concrete model developers.

This paper presents new and very simple numerical model for analysing reinforced and prestressed concrete structures. Paper could be very valuable to the researchers in this field as a benchmark for their analyses.

The purpose of this paper is to present a new numerical model based on a combined finite-discrete element method, capable of predicting the behaviour of reinforced concrete structures under dynamic load up to failure.

An embedded model of reinforcing bars is implemented in combined finite-discrete element code. Cracking of the structure was enabled by a combined single and smeared crack model. The model for reinforcing bars was based on an approximation of the experimental curves for the bar strain in the crack. The developed numerical model includes interaction effects between reinforcement and concrete and cyclic behaviour of concrete and steel during dynamic loading.

The findings provide a realistic description of cracking in the concrete structure, where all non-linear effects are realized in joint elements of the concrete and reinforcing bars. This leads to a robust and precise model for non-linear analysis of reinforced concrete structures under dynamic load.

This paper presents new robust finite-discrete element numerical model for analysis and prediction of the collapse of reinforced concrete structures. The model is capable of including the effects of dynamic loading on the structures, both in the linear-elastic range, as well as in the non-linear range including crack initiation and propagation, energy dissipation due to non-linear effects, inertial effects due to motion, contact impact, and the state of rest, which is a consequence of energy dissipation in the system.

A quadrilateral linear element for plane stress/plane strain analysis, formulated using a system of bars located at the Gauss integration points, is presented. A special bar element is formulated and the finite element is thereafter considered as an assembly of bars. The formulation presented is used in an attempt to explain the numerical problems arising when considering incompressible materials and reduced integration.

In this study, tests were conducted to investigate the effect of different concretes on the behaviour of reinforced concrete beams with central splices. Five beam specimens were prepared using different concrete mixes in their splice regions. Experimental results indicated that the bond failure of the spliced rebars governed the ultimate flexural behaviour of all specimens, except the one cast with steel fibres. A small increase in flexural strength was found for both the spliced beams cast with high‐strength concrete and steel fibres. Moreover, use of high‐strength concrete and steel fibrous concrete led to a remarkable improvement in the beam's displacement capacity. The effect of pulverised fuel ash on the splice performance was insignificant while the introduction of silica fume caused improvements in loading capacity and ductility.

This paper aims to investigate the fire performance of composite beams when considering the hogging moment resistance of the fin-plate beam-to-girder joints including the effect of continuity of reinforcements.

Experiments on composite beams with fin-plate joints protected only at the beam ends are conducted. The test parameter is the specification of reinforcement, which affects the rotational restraint of the beam ends. In addition, a simple method for predicting the failure time of the beam using an evaluation model based on the bending moment resistance of the beam considering the hogging moment resistance of the fin-plate joint and the reinforcement is also presented.

The test results indicate that the failure time of the beam is extended by the hogging moment resistance of the joints. This is particularly noticeable when using a reinforcing bar with a large plastic deformation capability. The predicted failure times based on the evaluation method corresponded well with the test results.

Recent studies have proposed large deformation analysis methods using FEM that can be used for fire-resistant design of beams including joints, but these cannot always be applicable in practice due to the cost and its complexity. Our method can consider the hogging moment resistance of the joint and the temperature distribution in the axial direction using a simple method without requirement of FEM.

A mixed approach to large strain elastoplastic problems is presented in a somewhat different way to that usually used within the context of the additive split of the rate of deformation tensor into an elastic and plastic part. A non‐linear extended mixed variational equation, in which the Jacobian of the deformation gradient and the pressure part of the stress tensor appear as additional independent variables, is introduced. This equation is then linearized in the accordance with the Newton‐Raphson method to obtain the system of linear equations which represent the basis of the mixed finite element procedure. For the case of a bilinear isoparametric interpolation of the displacement field, and for piece‐wise constant pressure and Jacobian, simplified expressions, differing from similar expressions corresponding to mixed finite element implementations, are obtained. The effectiveness of the proposed mixed approach is demonstrated by means of two examples.