近年，同調粘性マスダンパー(Tuned Viscous Mass Damper, TVMD)を用いたダンパー付アウトリガー構造が注目されています。TVMDとは，見かけの質量効果を利用するダイナミックマスダンパーの一種であり，粘性ダンパーと慣性接続要素を並列した粘性マスダンパー(VMD)に柔支持部材が接続され，両者の付加振動系の同調効果によって卓抜した地震エネルギー吸収性能を発揮します。これに対して筆者らは，既往研究にて実在する250m級中央コア型超高層建物を参考に設定した建物の数値解析検討と具体的な試設計を行い，(a)エネルギー吸収効果を自己増幅するTVMD付アウトリガー構造は曲げ剛性の確保が難しい日本のダンパー付アウトリガー構造の抜本的な解決策になること，(b)地震応答の包括的低減という観点では従来型と同様に1次モード制御が推奨されること，(c)TVMDは地震エネルギーを効率よく吸収できる位置に設置し過大な応答が生じないよう適切な質量比と軸力制限比を設定する設計が現実的かつ安価であり費用対効果が高いことを明らかにしました。一方，日本では，建築計画の都合で150m以下の超高層建物に片コア形式が使われる場合もあり，コア配置に依らず同応答制御構造が適用可能であると望ましいため，本研究では，典型的な日本の150m級片コア型超高層建物を対象にTVMD付アウトリガー構造の適用性と実現可能性を調査しました。本研究は日建設計との共同研究成果です。

本研究は日本免震構造協会の2025年度優秀修士論文賞に選ばれました！

論文はこちら

This paper examined a novel damped outrigger system with tuned viscous mass dampers (TVMDs) previously proposed by the authors for a typical Japanese side fore type tall building with 18 m of the outrigger span. A series of generalized response spectrum analysis and nonlinear response history analysis for a typical Japanese tall building with a center core was performed to investigate the seismic response reduction effect. Moreover, the structural detail was designed to estimate the cost and cost performance index, and the feasibility of the TVMD damped outrigger system was strictly discussed.

　中央コアから側柱までのスパン16m~20m が好まれる日本の超高層建物では，アウトリガートラスの曲げ剛性が海外より最大約20%まで劣化してしまい， ダンパーの接合部として十分な剛性を確保できないため，ダンパー付アウトリガー構造は国内では殆ど普及していません。これに対してエネルギー吸収効果を自己増幅できる同調粘性マスダンパー(Tuned Viscous Mass Damper, TVMD)は，曲げ剛性の確保が難しい日本のダンパー付アウトリガー構造の抜本的な解決策になると考えられており，都内超高層建物の耐震改修にも使用されていますが，その実現可能性には未だ不明な点が多いです。そこで本研究では，典型的な日本の中央コア型超高層建物を対象に，様々な質量比と配置を有するTVMD の応答制御効果を比較し，さらに現実的なケースを対象に具体的な納まりを設計し，導入費用を試算して実現可能性を評価しました。日建設計との共同研究成果です。やっと日本に適したダンパー付アウトリガー構造の解が得られて嬉しいです。論文はこちら

The damped outrigger system is known to efficiently provide additional damping in tall buildings. However, particularly for tall buildings in Japan, the outrigger truss from the center core to the exterior columns need to span distances of more than 16m. This is because Japanese developers prefer real estate that may maximize the leasable floor. This Japanese culture increases the flexural stiffness demand on the outrigger that leads to larger truss depths making the damped outrigger system inefficient, resulting that the damped outrigger is rarely adopted in Japan. To overcome this problem, following a successful example (available at https://xtech.nikkei.com/atcl/nxt/mag/na/18/00131/030300003/) of seismic retrofit of Japanese tall building, we proposed a novel damped outrigger system with tuned viscous mass dampers (TVMDs, a type of inerter). In the proposed system, the flexible outrigger truss is used as the the tuned spring for the viscous mass damper. In this paper, a series of complex modal analysis and nonlinear response history analysis for a typical Japanese tall building with a center core was performed to investigate the seismic response reduction effect. Moreover, the structural detail was designed to estimate the cost and cost performance index, and the feasibility of the TVMD damped outrigger system was strictly discussed.

　スリット配置の異なるオイルダンパー付ブレースチューブ構造の動的応答特性を調査しました。本研究は超超高層建物のパッシブ応答制御に関する研究シリーズの一つです。同応答制御システムの基本的な性能をフル立体で調べつくしたというものです。この研究も遂に3本目の論文となりました。論文はこちら

This paper investigated the dynamic response characteristic with focus on damped slit configuration of damped braced tube systems with oil dampers. According to the results, 1) damped braced tube system has over 10% 1st to 3rd damping ratio, 2) while the displacement and acceleration responses are simultaneously reduced up to maximized 1st mode damping ratio, the acceleration reduction effect may be getting worse after the peak, 3) while uniform damper distribution contributes to better damping performance, centralized damper distribution contributes to better period reduction.

　ダンパーの導入費用対効果という切り口で制振スリット付ブレースチューブ構造の最適地震応答制御を検討しました。本研究は超超高層建物のパッシブ応答制御に関する研究シリーズの一つです。論文はこちら

This paper presents design recommendations for optimal seismic response control of damped braced tube system with focus on cost performance of introducing energy-dissipation devices. According to the results, 1) braced tube structure should be designed so that coupled-shear-wall-like vibration modes are predominant to obtain highly damping ratio and better cost performance of dampers, 2) oil damper should be introduced to obtain highly damping ratio, 3) BRB has good cost performance about seismic response reduction and can be used to reduce damper costs.

　本論文では深刻な地震地域に立つ超高層建築のための制振スリット付ブレースチューブ構造を紹介しています。本研究は超超高層建物のパッシブ応答制御に関する研究シリーズの一つです。同応答制御手法の一般的な有効性を実証しました。2022年度のWiley top downloaded paperおよびWiley top cited paperに選出されました。論文はこちら

I would like to share my paper entitled “A novel damped braced tube system for tall buildings in high seismic zones” published in the structural design of tall and special buildings. The damped outrigger system is known to efficiently provide additional damping in buildings with heights of over 250m. However, particularly for supertall buildings in the center of Tokyo, Japan, the outrigger truss from the center core to the exterior columns need to span distances of more than 20?m. This increases the flexural stiffness demand on the outrigger that leads to larger truss depths making the damped outrigger system inefficient. For such tall buildings with large plans, a new damping modification system, the “damped braced tube system” is proposed, where the exterior surface of the elastic mega braces are partially removed vertically to create a split and are replaced with dissipaters (energy-dissipation devices). The damped braced tube system enhances the seismic performance as the exterior surfaces of the elastic mega braces work together with the damped slits like in a coupled wall system and increases the overall damping ratio. In this paper, numerical models were constructed based on a real project in Japan consisting of a 397-m supertall building employing the damped tubular braced system using oil dampers (referred to as viscous dissipaters). A series of generalized response spectrum based numerical analyses and optimizations were performed to minimize the seismic response. The proposed system exhibited improved damping performance with the first to third mode damping ratios reaching to more than 7% while providing a wide range of options for dissipater distribution for design. Finally, the elevation of the slit’s base is recommended to be equal to 0.22 of the total building height considering the trade-off relationship between the first modal damping ratio and the fundamental period.

　本研究では，地震動入力レベルを考慮したダンパー付単層アウトリガー構造の非線形動的応答特性を調査し，我々が提案する1次モード減衰比を最大化する最適設計の妥当性を検証しました。本研究は超超高層建物のパッシブ応答制御に関する研究シリーズの一つです。

・この研究を発展させたAI設計ツールはこちら

・論文はこちら

This paper investigated the non-linear dynamic response characteristic of single-damped outrigger systems with oil dampers or elasto-plastic dampers considering design earthquake levels. The optimal damper design equations to maximize 1st mode damping ratio were proposed, and validated through the application example of a Japanese super-tall building, and a design algorithm to translate the optimized single damped outrigger to quad damped outrigger systems is proposed.

　本研究は 一次モード減衰比に着目した線形粘性ダンパー付多層アウトリガー構造の最適設計法を提案しました。本研究は超高層建物のパッシブ応答制御に関する研究シリーズの一つであり，骨組モデルを用いた厳密な減衰性能評価から我々が推奨する同構造の一次モード減衰比最大化の有効性を示し，さらにその最適設計のための具体的なツール群を整備しています。併せてAI(機械学習)を利用した最適設計ツールのデモアプリも公開しているので遊んでみていただければ幸いです。私の星付き論文です。論文はこちら

The damped outrigger system is in widespread use as a damping modification system for tall buildings that provides high additional damping in addition to the bending back effect against the core. However, while the enhanced seismic performance of damped outrigger systems was confirmed in previous studies all over the world, a general-purpose optimal design method focusing on modal damping ratios has not been established yet. This paper proposes an optimal damper design kit composed of a first mode damping ratio oriented design policy, simple equations of optimal damper-connection stiffness ratio to maximize first mode damping ratio, a machine learning model to estimate first mode natural period and damping ratio. The tenability of the first mode damping ratio-oriented design policy was confirmed by performing complex modal analyses on single to quad damped outrigger systems incorporating linear viscous dampers and assigning realistic stiffness values to the outrigger trusses. The simple design equations of optimal damper-connection stiffness ratio and the machine learning model for first mode characteristics were developed based on a large number of analytical results. The proposed optimal design kit has been made available as a web application-based design tool.

　本研究は，非比例減衰を考慮した広範な数値モデルの各種数値解析を用いて，特にモード減衰比に着目したダンパー付アウトリガー構造の最適設計法の知見を拡充しました。本研究は超高層建物のパッシブ応答制御に関する研究シリーズの第一弾であり，博士課程の同級生がBRB付アウトリガー構造の地震応答特性を絨毯爆撃的な時刻歴応答解析で検討していたのに対して，対象を線形構造に限って複素固有値解析で丁寧に動的応答特性を確認してみようと思ったことが始まりでした。論文はこちら

The outrigger system incorporating dampers between the outrigger truss and perimeter column can significantly reduce dynamic response compared with the conventional one, and is becoming the most popular structural system for tall buildings in seismic regions except for Japan. While Smith and Willford who are the proposers of this damped outrigger system recommend to confirm the modal damping ratio in the design, there are few proposal of optimal design strategy based on the modal damping ratio. Therefore, this paper deeply investigated the relation between the modal property and the seismic response reduction by the single outrigger system with linear viscous dampers, and discussed 1st mode control design strategy. The section 2 outlines the general information of the numerical models and design parameters. The section 3 and 4 analyze the effects of the design parameters on the modal property and maximum seismic responses. The section 5 propose a simple formula of optimal damper stiffness ratio to maximize 1st mode damping ratio. The section 6 applied the proposed 1st mode control design strategy to a Japanese-type super tall building where aspect ratio is relatively small.