Combined with powerful mathematical capability of MATLAB and the excellent interfacial design function of GUIDE, a lifting optimization decision system for multiple-lifts-single-crane is proposed which is feasible in electrical equipment lifting tasks. Based on existing approaches, a novel algorithm is proposed for selecting appropriate cranes and determining their corresponding optimum locations, resulting a lifting optimization system. This system can minimize the number of crane locations on the premise of avoiding potential spatial conflicts. To investigate its performance, a case example is conducted. It is demonstrated that the utility of this system for multiple-lifts-single-crane lifting tasks which also allow users have a deeper intuitive judgment to the lifting process.

Generally, a substation involves a great many components, i.e., electrical equipment and precast elements, of large dimension and weight. Its lift planning has a major impact on construction sequence, scheduling, budgeting and safety. An optimization method for the scenario of single-cane-multiple-lifts is presented, mainly considering the objective to minimize the number of crane relocations. The method starts with identifying possible location zones by means of the constrained work envelope strategy and the grid traversal algorithm. Later, it adopts the multiple-target integer programming method to minimize the number of location zones that can lift all components, and then to maximize the total number of components that the available zones can lift including duplication. For each optimized zones, it checks the optimal location by means of the traversal algorithm, considering the minimum of the sum of the weighted load factors for all components. To avoid spatial interference, an automatic simulation is done by means of which any missing interference can be checked manually. Lastly, a case study is done to demonstrate the validity and practicality performance of the method.

Systems of ordinary di®erential equations (ODEs) arising from transient structural dynamics very often exhibit high-frequency/low-frequency and linear/nonlinear behaviors of subsets of the state variables. With this in mind, the paper resorts to the use of di®erent time integrators with di®erent time steps for subsystems, which tailors each method and its time step to the solution behaviors of the corresponding subsystem. In detail, a partitioned integration method is introduced which imposes continuity of velocities at the interface to couple arbitrary Newmark schemes with di®erent time steps in di®erent subdomains. It is proved that the velocity continuity of the method is the primal factor of its reduction to¯rst-order accuracy. To maintain second-order accuracy without increasing drift and computational cost, a novel method with the acceleration continuity is proposed whose velocity constraint is also ensured by means of the projection strategy. Both its stability and accuracy properties are examined through numerical analysis of a Single-degree-of-freedom (DoF) split mass system. Finally, numerical validations are conducted on Single-and Two-DoF split mass systems and a four-DoF nonlinear structure showing the feasibility of the proposed method.