Supertall Building Construction Research Articles

Experimental Study for Structural Behavior of Embed Plate into Concrete Subjected to Welding Heat Input

In a super-tall building construction, thick and large-sized embed plates are usually used to connect mega structural steel members to RC core wall or columns by welding a gusset plate on the face of the embed plate with T-shape. A large amount of heat input accumulated by weld passes causes the plates to expand or deform. In addition, the temperature of concrete around the plates also could be increased. Consequently, cracks and spalls occur on the concrete surface. In this study, the effect of weld heat on embed plates and 80MPa high strength concrete is investigated by considering weld position (2G and 3G position), edge distance, concrete curing time, etc. Measured temperature of the embed plates was compared with the transient thermal analysis results. Finally, push-out tests were performed to verify and compare the shear studs capacity of the embed plate with design requirement. Test result shows that the shear capacity of the plate is reduced by 14%-19% due to the weld heat effect and increased as the concrete curing time is longer.

Lifting load calculation method of computing simulation for super-tall building construction

Lifting load calculation method of computing simulation for super-tall building construction

건설 리프트 가감속 능력을 고려한 양중시간 산정 알고리즘 개발

초고층 건축공사에 있어서의 건설리프트 설치는 여러 가지 제한조건들에 의해 한정적인 대수만이 설치될 수 있으며, 이러한 건설리프트의 특징에서 기인하는 설치의 제약은 수직동선 관리에 의해 변화하는 각 층별 노무 생산성에 밀접한 영향을 미치게 된다. 따라서 초고층 건축공사에 있어서의 리프트 운영관리는 현장의 작업생산성을 결정하는 중요한 관리요소이나, 현재 초고층 건축공사의 건설리프트 운영계획의 경우, 각 건설사별 다른 기준을 바탕으로 해당사의 숙련 기술자들의 경험에 의존하는 형태로 계획 및 관리가 이루어지고 있으며, 이러한 관리형태는 프로젝트가 초고층화 및 대형화됨에 따라 고려하지 못하거나 착오가 발생할 수 있는 부분이 생길 수 있는 리스크를 가지고 있다. 이에 본 연구에서는 초고층 건축공사의 중요한 관리요소인 건설리프트 양중관리 시뮬레이션 개발의 일환으로, 건설 리프트의 가감속 능력을 고려한 양중계획 시간산정 알고리즘을 개발하고, 개발된 알고리즘에 대해 시뮬레이션 및 현장측정을 통해 검증하였다. An installation of the construction lift has a few limitations by many constrains and these have influences on labor productivity, that can be changed by vertical-transportation management. In the super-tall building construction, a management of construction lift operation is one of the most important factor, but existing methodologies depend on skilled practitioners' experiences. And it is true that the expertise resulted by the experiences does not transfer to the next generation. This study is a part of lifting-management simulation development which aims at the optimal construction lift management. A proposed algorithm is focus on lifting time calculation considering an acceleration capability. This research evaluates the result accuracy using comparative analysis on simulation result and field measuring time.

초고층건축요소별 법제도 개선방향

최근 초고층건축 사업추진 및 수행을 위한 관련 기술개발과 함께, 사업 추진을 지원하기 위한 관련 법 제도개선의 필요성이 증대되고 있다. 이에 따라 국토해양부 초고층복합빌딩사업단에서는 초고층복합빌딩 법 제도 및 지원정책관련 연구를 진행하고 있으며, 본 연구는 1차년도 결과의 일부로서, 초고층 건축 지원을 위한 법 제도 및 지원정책 관련 이슈와 문제점을 파악하여 초고층복합빌딩 기술요소 유형별 분류체계를 구축하고, 항목별 중요도 및 현황수준평가를 통해 개선방향을 도출하는 것을 목적으로 하였다. 초고층 프로젝트 생애주기에 따라 총68개의 기술요소를 도출하였으며, IPA방법론을 적용하여 중요도 및 현황평가를 실시하였다. 또한 글로벌기준의 초고층 법 제도 개선방향을 도출하였으며, 초고층을 중심으로 하는 국내 건축 관련 법 제도 선진화의 기반이 될 수 있다. Recently, with development of core technology for supertall building construction projects, the need for an improvement of the related legal system is increasing dramatically. Therefore, the supertall Buildings R&DB Center, which is funded by the Ministry of Land, Transport and Maritime affairs (MLTM), is studying the legal system for supertall buildings. This research, as one part of the 1st year research results, aimed at studying supertall building project related issues and problems to develop supertall building elements, and conducting an importance-performance analysis (IPA) of these elements in order to conclude a strategy and direction for an improvement of the related legal system. A total of 68 supertall building elements were derived, and the IPA method was used to analyze these elements based on attribute types. Furthermore, an improvement strategy and directions were suggested for upgrading the legal system related to supertall buildings to the level of global standards. These efforts can be the base for advancing the legal systems of the domestic construction industry in all areas, including supertall building construction.

프로젝트 공사기간과 연계된 극 초고층 타워크레인 최적화 선정에 관한 연구

It is critical to select the appropriate type of tower cranes for the construction of super tall buildings. However the selection is often made based on subjective personal experiences due to the lack of historical and analytical data. As a result, planning mistakes and efficiency errors sometimes occur. This research is to develop a system of hoisting analysis for appropriate tower crane selection and to provide a flexible statistical model based on the Burj Dubai project. In addition, this system hassupporting functions that can estimate the target construction period per floor, and a decision-making construction period computation method which is based on the characteristic of the selected tower cranes.

Study on semi-active control of mega-sub controlled structure by MR damper subject to random wind loads

The recently proposed mega-sub controlled structure (MSCS), a new type of structure associated with the design and construction of super-tall buildings, has attracted the attention of designers for use in enhancing the control effectiveness in mega-frame buildings. In this paper, a dynamic equation and method to assemble parameter matrixes for a mega-sub controlled structure under random wind loads is presented. Semi-active control using magnetorheological dampers for the MSCS under random wind loads is investigated, and is compared with a corresponding system without dampers. A parametric study of the relative stiffness ratio and relative mass ratio between the mega-frame and the substructures, as well as the additional column stiffness ratio that influences the response control effectiveness of the MSCS, is discussed. The studies reveal, for the first time, that different control mechanisms exist. The results indicate that the proposed structure employing semi-active control can offer an effective control mechanism. Guidelines for selecting parameters are provided based on the analytical study.

Controlling Characteristics of Passive Mega-Subcontrolled Frame Subjected to Random Wind Loads

The passive mega-subcontrolled structure proposed recently is a new form of structure associated with the design and construction of supertall buildings. However, a shortcoming still exists in its structural configuration. In this paper, a new configuration of the passive mega-subcontrolled frame is proposed. A more realistic analytical model of this structure subjected to random wind loads is presented, in which the substructures are treated as a multi-degree-of-freedom (MDOF) system and a nonwhite stochastic process in time and space is used. The dynamic equations and the response spectrum expressions, as well as the mean square response expressions, are derived on the basis of complex modal-analysis theory. A practical steel passive mega-subcontrolled frame is investigated; it is designed with reference to the conventional mega-subframe used in the Tokyo City Hall. The influence of the relative mass ratio and the relative stiffness ratio on the controlling effectiveness is investigated; and a proposed relative stiffness region, which is very useful in practical engineering design, is first presented. The corresponding computing results demonstrate that the structural configuration proposed here has extraordinary effectiveness in controlling displacement responses and acceleration responses, and the shortcoming that existed in the previously presented configuration can be overcome effectively.

The controlling mechanism and the controlling effectiveness of passive mega-sub-controlled frame subjected to random wind loads

The passive mega-sub-controlled structure proposed recently is a new form of structures associated with the design and construction of super tall buildings. However, as the dynamic characteristics of a practical passive mega-sub-controlled structure are very complicated, it is difficult to further all-sidedly examine the performance and the controlling effectiveness of this structure by a simple analytical model. In this paper, a new practical steel passive mega-sub-controlled frame is designed with reference to the conventional mega-sub-frame used in Tokyo City Hall. A more realistic analytical model of this structure subjected to random wind loads in which a non-white stochastic process in time and space is used is presented, and the coherence of the wind loads is further considered. The dynamic equations and the response spectrum expressions as well as the mean square response expressions are derived based on complex modal analysis theory. Moreover, the relative mass ratio RM and the relative stiffness ratio RD between the megaframe and the substructures are defined. The controlling effectiveness with different RM and RD is investigated. The results show that there exist some different controlling mechanisms, which are for the first time detected in this paper. As RD is less than certain value, RD<0.477 for this building, the first vibration mode or the first–second vibration modes can be suppressed, and a remarkable controlling effectiveness can be obtained. However, as RD is greater than this value, the first vibration mode cannot be suppressed; the controlling effectiveness is unacceptable and is not like the expectations reported in earlier references.