In this article the method of minimization of downtime in scheduling construction works is presented. Essentially, the method is based on the assumption of brigade multitasking. This phenomenon is currently being noti...
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In this article the method of minimization of downtime in scheduling construction works is presented. Essentially, the method is based on the assumption of brigade multitasking. This phenomenon is currently being noticed at Polish construction sites. The goal of the author was to develop a method based on mathematic removal of downtime which would let take advantage of the brigade multitasking at the stage of processing the scheduling of construction works. In this article the description of the method is presented, as well as an example of its application.
This work summarizes assessing the durability results of facade coatings in the area of their resistance of the self – cleaning effect. To characterize this feature three different types of samples were chosen: silic...
This work summarizes assessing the durability results of facade coatings in the area of their resistance of the self – cleaning effect. To characterize this feature three different types of samples were chosen: silicone paint, photocatalysis effect paint and lotus flower effect paint. Test samples were exposed on natural conditions and artificial weathering process in laboratory at the same time. After this research, durability effect of self – cleaning properties and stain resistance by established criteria were obtained. LM and SEM micrographs, contact angle and profilometry were used widely to measure this factor. In conclusion, all of tested facade coatings based on silicon exhibit the highest effect of self-cleaning.
A European pressurized reactor （EPR） steel containment liner structure is comprised of the cylinder part and the dome part. An introduction of the steel liner structure is presented, followed by studies on the key m...
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A European pressurized reactor （EPR） steel containment liner structure is comprised of the cylinder part and the dome part. An introduction of the steel liner structure is presented, followed by studies on the key mechanical features of the construction process using a refined finite element method. The steel liner was divided into several modules and then assembled during construction. Firstly, the equipment structure used to hoist the liner module was optimized, the lifting lug was analyzed using a multi-scale finite element model; the wind speed limit during lifting was also studied. Subsequently, the effect of internal forces during assembly between the liner modules, the lateral pressure of fresh concrete, the non-uniform temperature load, and the wind load on the cylinder module was analyzed. According to the time-varying structural performance during continuous concrete pouring and the hardening construction, an ＂overlapping element and birth-death element＂ technique was adopted to analyze the deformation and stress of the long-span steel dome liner. In addition, the stability-bearing capacities of the dome structure during construction were also studied, which took into consideration the effect of the initial geometrical imperfections and the elasto-plasticity of the material. This study presents a reference in terms of the mechanics of the construction scheme and the safety of such a type of structure.
There is growing interest within the construction industry in using Grade 600 reinforcing steel for certain applications. There are areas where Grade 600 steel reinforcement can help include improvement in constructio...
There is growing interest within the construction industry in using Grade 600 reinforcing steel for certain applications. There are areas where Grade 600 steel reinforcement can help include improvement in construction efficiencies and reduction in manpower. However, the implementation of these Grade 600 reinforcements in designs and construction still pose some challenges, as a number of unresolved design issues still remain. Notably current EC 2 design provisions do not provide explicit guidelines on the use of these high strength steel reinforcements and may not have addressed some distinctive performance characteristics. This paper lists potential issues with the use of Grade 600 reinforcement, and also provides a comprehensive assessment of available literature on the impact of Grade 600 steel reinforcement on design practices.
When project teams are pressured to limit internal or external Lean coaching due to budgetary concerns, Lean coaches may not have sufficient time to guide project teams in materials management to support milestones. C...
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When project teams are pressured to limit internal or external Lean coaching due to budgetary concerns, Lean coaches may not have sufficient time to guide project teams in materials management to support milestones. Consequently, while organized project teams will make the time to develop a strategy for managing key materials that impact the critical path, disorganized project teams will more likely manage most materials on an ad-hoc basis. This lack of a materials management strategy then leads to unrealized profits and hidden wastes on projects. As a result, this research seeks to investigate how to develop a basic materials management framework to help project teams begin determining which bulky materials should be: (1) Using a pull system (e.g., through the use of Kanban cards or milk runs) to coordinate deliveries, (2) Kitted off-site vs. on-site, and (3) Organized into prefabricated assemblies. Specifically, this paper will identify various questions, calculations, and artefacts (e.g., equipment for handling and staging materials, signage used to make the materials management strategy transparent to all project participants) that contribute to establishing a comprehensive materials management strategy. In particular, space management emerges as an important tool to organize the flow of materials to match job-site installation rates.
This paper studies the influence of highway vehicle loads on the vibration of nearby buildings, and both the vehicle induced vibration of ground and adjacent residential are analyzed. Firstly, testing points are arran...
This paper studies the influence of highway vehicle loads on the vibration of nearby buildings, and both the vehicle induced vibration of ground and adjacent residential are analyzed. Firstly, testing points are arranged on both sides of a highway named Xiongchu Avenue to measure the ground vibration caused by vehicle loads. Secondly, the corresponding vibration response of a nearby residential building is measured. The natural frequency of this building is identified by NexT/ERA method. The results show that the influence of the traffic load on the frequency of the building is mainly between 8Hz to 20Hz. The acceleration level of each storey and influence of vibration on human comfort are calculated, and it is concluded that all the degree of vertical vibration are belong to the requirements in the Chinese code. This paper provides corresponding technical support for solving the problem of such traffic system.
In this study, a 60/70 penetration grade bitumen was modified with polyurethane (PU) added with a Warm Mix Asphalt (WMA) additive, i.e. Cecabase, in the amount of 0.5 wt % with respect to bitumen. The thermal characte...
In this study, a 60/70 penetration grade bitumen was modified with polyurethane (PU) added with a Warm Mix Asphalt (WMA) additive, i.e. Cecabase, in the amount of 0.5 wt % with respect to bitumen. The thermal characterization was done using the Differential Scanning Calorimetry (DSC) while the chemical analysis was done using Fourier Transform Infrared (FTIR). Raman Spectroscopy was used to characterize the asphaltic materials in the bitumen, namely the D (Defect) and G (Graphite) bands. Test results showed that adding PU and Cecabase to the bitumen slightly shifted the Tg and Tm peaks of the thermal behaviour. The result of FTIR showed that there was no shift in the carbonyl and sulfoxide peaks, which indicate that no chemical interaction occurred in the unmodified and modified bitumen. Furthermore, the Raman Spectroscopy investigation revealed that PU and Cecabase reduced the wax content and decreased the bee-structure of the bitumen samples. However, the order structures of unmodified and modified bitumen were still within the boundary limit of the D and G bands of the Raman spectra. In conclusion, the use of PU and Cecabase as bitumen modifier are promising for alternative source for bitumen.
The article is a proposal of development of anhydrite screed and subsequently carrying out samples of examination of anhydrite screed without fibres and with different kinds of fibres. Furthermore, there are mentioned...
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A vibration serviceability assessment of footbridges is required in design stage to evaluate the response to human-induced excitation. If the calculated response does not meet the desired criteria for vibration comfor...
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A vibration serviceability assessment of footbridges is required in design stage to evaluate the response to human-induced excitation. If the calculated response does not meet the desired criteria for vibration comfort, a Tuned Mass Damper (TMD) can be installed as a vibration mitigation device. The TMD mass, stiffness and damping constant must be tuned to the modal parameters of the structure to obtain the desired response reduction. The response prediction and TMD design rely on a good knowledge of the modal parameters of the footbridge and usually assume that the response is governed by a perfect harmonic loading causing resonance. Differences between the predicted and actual modal parameters may lead to both an unreliable response prediction and a suboptimal TMD performance. Therefore, a robust design of the TMD is proposed accounting for uncertainties in the modal parameters. Realistic walking scenarios of continuous pedestrian traffic are simulated to obtain an effective response reduction by the TMD. In this contribution, the robust design of a TMD is demonstrated for a slender footbridge accounting for reasonable levels of uncertainties in the modal parameters. Numerical optimisation is therefore applied and vibration serviceability requirements are imposed as design constraints. The obtained TMD parameters are compared to those obtained from the formulae proposed by Asami, determining the stiffness and damping constant as a function of its mass. It is found that the TMD mass can be further reduced when the TMD parameters are tuned independently from each other compared to the classical design according to Asami but a higher computation cost is needed. Furthermore, an increasing degree of robustness against variations in the modal parameters is obtained by increasing the TMD mass and damping.
作者：
Juhyung, LeeDo, JinungGeotechnical Engineering Research Institute
Korea Institute of Civil Engineering and Building Technology 283 Goyangdae-Ro Ilsanseo-Gu Goyang-Si Gyeonggi-Do411-712 Korea Republic of Dept. of Civil
Construction and Environmental Engineering North Carolina State Univ. 208 Mann Hall Campus Box 7908 RaleighNC27695-7908 United States
In this study, a new type of suction pile foundation for floating structures, namely group suction piles, was proposed to improve the shortcomings of conventional single suction piles. Small-scale model tests were per...
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