Application of Modal-Displacement Based Design Method to Multi-Story Timber Blockhaus Structures

Abstract

Structures under seismic excitation undergo different inter-story drift levels that can be associated to damage of both structural and non-structural elements, and thus to the expected losses. The Modal-Displacement Based Design (DBD) procedure, in this regard, has been developed to fix major issues of Force Based Design (FBD) approaches, thus to design multi-story buildings in which the inter-story drift can allow one to control damage mechanisms. In this paper, the conventional Modal-DBD methodology is applied to multi-story timber buildings constructed using the Blockhaus technology. Given their intrinsic geometrical and mechanical features (i.e., stacking of logs, door/window openings, gaps and friction mechanisms, etc.), dedicated methods of analysis are required for them, compared to other wooden structures. A three-story case-study Blockhaus system of technical interest is thus presented for the assessment of Modal-DBD calculation steps. As shown, special care must be spent for the selection of convenient inter-story drift limits that in general should reflect the characteristics of the examined structural typology. The backbone parameters are thus collected for each shear-wall composing the 3D Blockhaus building, based on refined Finite Element (FE) analyses of separate log-walls. The overall results of the Modal-DBD process are thus finally assessed by means of a Push-Over (PO) analysis, carried out on a simplified 3D FE model of the examined multi-story structure. The comparison of FE predictions, as shown, demonstrates that reliable estimates can be obtained when the Modal-DBD procedure is applied to timber Blockhaus systems. In particular, base shear loads can be estimated with good accuracy, while the corresponding top displacements are slightly overestimated (with up to +10%–14% the expected values, for the collapse prevention performance level).

From Trees to Skyscrapers: Holistic Review of the Advances and Limitations of Multi-Storey Timber Buildings

“…In addition, as part of the findings, methods to facilitate the modeling of multi-storey timber buildings are described [47,105,[110][111][112][113][114]116,117,119,123,124,132,133,136,139,140,142], along with simulations based on experimental test results [21,31,[120][121][122]125,127,130,134,135].…”

Seismic Vulnerability Assessment and Strengthening of Heritage Timber Buildings: A Review

“…For the log house system, shear walls are the lateral load-bearing system, and the procedure for the simulation of this structural system is the same as in the case of timber frame system, which is employed in [51][52][53]. As illustrated in Figure 9a, the friction pendulum link element was used to model friction between the contact surfaces of the logs, and an inclined equivalent spring was modeled to simulate the interlocking between the logs [51].…”

Parameter identification procedure for hysteretic shear-resistant properties of beech wood dowels

“…Additionally, Blockhaus timber structures show great seismic performance during both the experiments and actual usage (Branco et al 2013;Tomasi and Piazza 2013). Therefore, Blockhaus structures are widely built in areas of the world having a high percentage of forest cover (Bedon and Fragiacomo 2019;Sciomenta et al 2020).…”