著者

中野 達也 倉成 真也 田渕 基嗣

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.83, no.744, pp.321-331, 2018 (Released:2018-02-28)

参考文献数

12

被引用文献数

2

---

In this study, beam-end connections of a steel structure using a pre-built-up H-shaped beams by submerged arc welding (SAW) are targeted, the structural characteristics is evaluated, the design and construction methods to prevent early brittle fracture are investigated. In this paper, first the influence of the welding construction conditions to the toughness of SAW metal was investigated, next the influence of the toughness of SAW metal to the structural characteristics of the beam-end connection were investigated by the full-scale cyclic loading test. The influence of the welding construction conditions to the toughness of SAW metal was investigated for two kinds of weld metals. One is a fillet weld metal by one-pass of tandem electrodes SAW, the other is a weld metal by multi-layer and multi-pass of single electrode SAW conforming to JIS. The test results showed that the toughness of the fillet weld metal was lower than that of the JIS weld metal. The toughness of SAW metal depended on a flux, was less affected by a steel material and a welding wire. The Charpy absorbed energy at 0°C (vE0) increased with the increase of the basicity of the flux. The fracture situation and the structural characteristics of the beam-end connection were investigated by the full-scale cyclic loading test in which the parameter is the toughness of SAW metal. Three specimens were provided, vE0 of SAW metal is 15J, 48J and 59J. In all the specimens, vE0 of the base metal of beam flange was 165J and the non-welding part remained in the fillet weld by SAW. In test result of all specimens, the point of crack initiation was the bottom of weld access hole and the brittle fracture occurred at the beam-end flange joint. The conversion position from ductile fracture to brittle fracture is inside SAW metal in case that vE0 of SAW metal is 15J, near SAW bond line in case that vE0 of SAW metal is 48J and 59J. As for the structural characteristics of the beam-end connection, it became clear that the maximum bending strength and the plastic deformation capacity of the beam-end connection increased with the increase of the toughness of the SAW metal in the range where the toughness is low. In case that vE0 of SAW metal is 15J, the plastic deformation capacity was about 40% of the required performance. On the other hand, in cases that vE0 is 48J and 59J, the required performance was satisfied. From the above results, it is considered that the influence of the toughness of SAW metal to the plastic deformation capacity of the beam-end connection using pre-built-up H-shaped beam is serious. It is certain that early brittle fracture occurred in case that SAW metal had low toughness, even though the base metal of beam flange had high toughness. On the other hand, it became clear that the plastic deformation capacity exceeding the required performance can be obtained by ensuring the toughness of SAW metal, even if the brittle failure occurred. If the weld access hole are provided at the beam-end connection using pre-built-up H-shaped beam, it is necessary to ensure the toughness of SAW metal by paying attention to the selection of the wire and the flux used for SAW.

著者

岡﨑 智仁 河野 守

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.81, no.720, pp.369-376, 2016 (Released:2016-02-28)

参考文献数

18

---

A story of a building may collapse due to excessive column inclination caused by thermal elongation of connecting steel beams during fire. However, thermal elongation of steel beams is not investigated fully. It can be thought that the thermal elongation is restrained by the rigidity of adjacent members. Their restrain effects are modeled by a spring at the end of the heated beam. From the consideration of full scale fire furnace tests of steel beams which were constrained by the RC slab, it can be assumed that the constraining effect of the RC slab is presented by its bending stiffness. Furthermore, the stiffness reduction can be indicated by an exponential equation. This study indicates that the thermal elongation of steel beams can be predicted accurately by the simple theoretical formula for the performance based fire engineering design.

著者

石渡 康弘 伊藤 有美 小松 博

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.83, no.746, pp.647-657, 2018 (Released:2018-04-30)

参考文献数

13

---

Since people's awareness about the importance of energy conservation and recycling of materials has increased in recent years, various projects to build a recycling society have been initiated. In the field of architecture also, we are faced with the need to recycle resources and reduce environmental impact, by taking actions to utilize renewable resources. Therefore, we have directed our attention to the recycling of aluminum and wooden materials as renewable resources from the viewpoint of solving global environment issues. With this background, this paper proposes a composite structural column made of two different materials, aluminum and wood, in which wood is introduced into the aluminum box sectional member. Since aluminum material requires a step of anodized aluminum welding, it has been thought that utilization as a structural member was unlikely to spread. However, since the approach proposed in this paper does not necessitate such welding, this opens the possibility of using joint hardware pieces such as screws and bolts in the same manner as used when jointing construction members in steel structure construction and the timber frame method. Furthermore, with the use of a composite structural column as proposed by this paper, we conclude that the different materials of the composite structural column can make up for the drawbacks of each material, for example, controlling variations in bearing force in the timber and preventing local buckling in the aluminum. Through this study, we plan to verify, with loading tests, whether such a composite structural column which is made of an aluminum box section with a wood member inside, is actually applicable to utilization in the field, and from the test results obtained, to introduce a formula for evaluating bearing force to identify the characteristics and values in use for the composite structural column. We compared the characteristics of bending, shearing and compression of three specimens of an aluminum box section, a simple wood column and an aluminum-wood composite structural column, using pure bending tests, shearing tests, short column compression tests, and bending-buckling tests. By doing various experiments, we aimed to determine the structural characteristics of the composite structural column through comparison with the characteristics of a simple wood column to identify prospective application fields. From the results of the experiments, we determined the structural characteristics of a composite structural column which is composed of an aluminum box section with wood inside, and proposed a related bearing force evaluation formula. In comparing the composite structural column specimen with a simple wood specimen and a specimen of aluminum box section, we confirmed that the composite structural column has improved mechanical characteristics such as bearing force and deformation performance. This composite structural column was verified to have a sufficient performance for practical application in the field.

著者

桑村 仁 礒崎 あゆみ

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.67, no.556, pp.159-166, 2002-06-30 (Released:2017-02-04)

参考文献数

15

被引用文献数

15 20

---

Ultimate behaviors of mechanically fastened shear type connections of thin stainless steel plates were investigated on the basis of quasi-static tensile test of 90 specimens. The specimens were formed from SUS 304 flat plates of 1.5mm and 3.0mm thickness and an SUS304 angle section of 3.0mm thickness, the connections of which were fastened by SUS 304 ordinary strength bolts of M12 and M16,and SUS 630 high-strength bolts of M12. Major observations are : four fracture modes, i.e., net section fracture, end opening fracture, block shear fracture, and fastener shear fracture were observed ; current design method has a difficulty in predicting the fracture mode which should take place among the four modes ; and current design formulae tend to overestimate the ultimate strength. From these facts, modified formulae for calculating the ultimate strength were proposed, which were found to provide a satisfactory prediction for failure mode and ultimate strength.

著者

木本 次憲 稲山 正弘

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.74, no.644, pp.1795-1802, 2009-10-30 (Released:2010-01-22)

参考文献数

4

---

The oldest wooden temple in the world “Horyuji-Kondo” consists of a framework of interlocking members; cloud-shaped bracket sets, diagonal tail rafters, horizontal brackets and wooden dowels which construct triangular trusses together. The axial force effect has not been cleared yet, but the tension of tail rafters should be supported by horizontal pre-tensioned arms like a whole space-frame. We try to analize the structural system of the ancient temple 1300 years ago by the experiments of 1/2 scaled models.

著者

竹内 徹 堀内 健太郎 松井 良太 小河 利行 今村 晃

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.79, no.703, pp.1309-1319, 2014-09-30 (Released:2014-09-30)

参考文献数

16

被引用文献数

5 5

---

Although truss towers used for telecommunication, electric power transportation, supporting structures for smokestacks in power plants have been designed against wind loads, a higher level of safety is recently required because of the increase of anticipated large seismic inputs. The ultimate strength of these structures is governed by tubular member buckling which is easily led to member fracture. This paper proposes the post-fracture analysis methods for truss structures composed with tubular members of large diameter-to-thickness ratios, and study on the collapse mechanism of such truss towers after the buckling and fracture of main columns and diagonals are investigated, using IDA analyses taking these member fractures into account.

著者

萩下 敬雄 大崎 純

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.73, no.633, pp.1959-1965, 2008-11-30 (Released:2009-10-28)

参考文献数

24

被引用文献数

1 1

---

A new approach integration heuristics and nonlinear programming is proposed for topology optimization of discrete structures under stress and local buckling constraints. In the approach, the optimal ground structures are searched by heuristics, and topology optimization is performed for each ground structure based on nonlinear programming. Two heuristics are applied; namely, tabu search, and a new heuristic method called topology mining, which is based on the apriori algorithm. Three numerical examples are solved to demonstrate the effectiveness of the proposed approach. Moreover, the efficiency in view of computational cost of the two heuristics is discussed by comparing the optimization results.

著者

崔 京 蘭 大崎 純 中村 奎吾

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.82, no.737, pp.1137-1143, 2017 (Released:2017-07-30)

参考文献数

21

被引用文献数

1 2

---

Recently, a number of designers have focused on free-form surface shell to realize a free architectural form that is different from the analytical curved surface such as cylindrical or spherical surfaces. However, in order to create rational architectural forms, constructability and cost are also essential factors to be considered. Developable surface is a special form of ruled surface generated by continuous movement of the straight line. It can be obtained by adding the condition that the normal vector of the surface does not change along the generating line (generatrix). Because the generatrix is a straight line without torsion, the formwork of continuum shell is easily created. Since the twisting process is not required, it has a high workability characteristics. In this study, several developable surfaces are combined to form a curved roof structure. The (n,1) Bézier surface is used for modeling the surface. Optimization problem is formulated for minimizing the maximum principal stress under several static loading conditions including vertical and horizontal loads. The coordinates of control points of the Bézier surface are chosen as design variables. The developability condition is numerically assigned so that the tangent vectors at the same parameter value of the two Bézier curves along the boundary exist in the same plane as the directing line. The G0 and G1 continuity conditions are assigned for connecting the Bézier surfaces. Optimal solutions are found using nonlinear programming approach, where the sensitivity coefficients are computed by the finite difference approximation. As the result of optimization, a variety of developable surfaces are obtained by connecting Bézier surfaces. Since the control points of the curves are chosen as design variables, the calculation efficiency is high. The stress distribution also greatly improved by using the maximum stress as the objective function.

著者

姜 容学 三上 貴正

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.77, no.676, pp.815-821, 2012-06-30 (Released:2012-07-27)

参考文献数

14

---

Steps are common features in our day-to-day living and working environment. Unfortunately, the occurrence of accidents on or around steps is thus inevitable. A failed visibility to see or recognize a step remains the most common attribute in these accidents. Surprisingly, appropriate methods for examining and quantifying step visibility have yet to be established. In this research, sensory scales of step visibility were created in order to examine the effects of two factors on step visibility in sensory testing methods; observation distance from step and observation action while viewing a step from the descending direction. Results of sensory and statistical tests revealed that step visibility tends to decline as observation distance increases, and the quality and tendency of step visibility in different observation conditions varies based on the unique and individual visual characteristics of each step.

著者

李 柱国 李 慶濤

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.76, no.666, pp.1375-1382, 2011-08-30 (Released:2012-01-13)

参考文献数

14

被引用文献数

1 2

---

When concrete is exposed to high temperature, its properties will deteriorate. Clarifying the property recovery extent of fire-damaged concrete and influencing factors, and developing improvement technology of property recovery are importance issues for repairing and strengthening concrete structure after suffered a fire. In this study, a series of concrete specimens with water-cement ratios of 50% and 35% were heated in an electric furnace at an elevated temperature in a range of 200-750°C. The recoveries of compressive strength, elastic modulus, and carbonation resistance after heated were investigated. We discussed the effects of strength grade of concrete before heated, heating temperature, cooling method, and recurring method and period on the recovery extents. Also, a kind of impregnating agent was used to improve the recovery extents. The experimental results clearly indicated that the use of impregnating agent could greatly promote the property recovery of heated concrete.

著者

平井 敬 福和 伸夫

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.77, no.673, pp.341-350, 2012-03-30 (Released:2012-07-02)

参考文献数

15

被引用文献数

1

---

The 2011 off the Pacific coast of Tohoku Earthquake (M 9.0) is the greatest earthquake in Japan. Analysis of GPS network, such as GEONET by Geospatial Information Authority of Japan, has revealed the crustal deformation distribution due to the earthquake. On the other hand, the crustal deformation distribution can be estimated from the displacement waveform calculated by integrating the accelogram observed by strong motion seismometer. This method would be used complementary with GPS analysis. In this study, we calculated the crustal deformation distribution due to the 2011 off the Pacific coast of Tohoku Earthquake from the accelograms recorded on strong motion observation network K-NET and KiK-net by National Research Institute for Earth Science and Disaster Prevention. The crustal deformation distribution calculated from strong motion records is consistent with that by GPS observation. In addition, the displacement waveforms estimated from strong motion records are in good agreement with that from 1 Hz GPS analysis.

著者

山田 有孝 永野 正行 山添 正稔 三浦 賢治

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.67, no.561, pp.73-80, 2002-11-30 (Released:2017-02-04)

参考文献数

20

被引用文献数

1 1

---

The earthquake strong motion arrived from seismic fault via propagating in bedrock and local site. The adequate 3-dimentional dynamic analytical method is required in order to evaluate the seismic risk for the coming large earthquake. The development of computer technology makes it possible to carry out the dynamic analysis of huge 3-dimentional soil model. The finite element method (FEM) applied to space discrete and explicit method applied to time integration is useful. The FEM can represents soil irregularity more rigorous but expense longer computational time. This paper describes the method of FEM and explicit time integration considering multi volumes with variable mesh size and integral time increment. The proposed method demonstrates good computational performance for dynamic analyses of large 3-dimentional soil model. The prediction analyses for earthquake motions in Osaka area during hypothetical Tokai-Nankai earthquake is shown.

著者

佐藤 篤司 三井 和也 青山 雅弘

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.82, no.736, pp.929-939, 2017 (Released:2017-06-30)

参考文献数

17

---

Steel products which have various characteristic (e.g. high ductility, high yield stress, low yield stress and high weldability) are used as main structure of building by diversification of demanded application, and technology for steel manufacturing has developed. Because steel square tubular member is processed cold-forming and welding in the process of manufacturing, residual stress will exist in the products. Moreover, due to the cold-forming process geometrical initial imperfection, i.e., global and local, will exist. These initial imperfections are still remained even so the technology for steel manufacturing is developed. The influence of the initial imperfection on the performance of the column is well known. However, the effect of the initial imperfection on the elasto-plastic behavior of square steel tubular columns under compressive axial force with one end bending moment is not clarified. In this paper, firstly, the effect of initial imperfection (i.e., initial global imperfection, initial local imperfection or residual stress) on the elasto-plastic performance is investigated independently; comparison between the experimental results are shown. Secondly, the effect of composite initial imperfections on the elasto-plastic performance is investigated. Firstly, followings were found from the analysis results where initial imperfection is introduced in the member individually. 1) The amplitude of the global imperfection has an impact on performance of the column. Also, the direction of the global imperfection has an impact on performance of the column. When the ultimate behavior was determined by local buckling, the deformation capacity decreased with an increase the amplitude of global imperfection to windward. On the other hand, when the ultimate behavior was determined by bending deformation in in-plate, the deformation capacity increased with an increase the amplitude of global imperfection. 2) The amplitude of the local imperfection has a great impact on performance of the column. The maximum bending moment and the deformation capacity significantly decreased with an increase the amplitude of local imperfection. 3) The magnitude of the residual stress which changes in plate thickness direction hardly has an impact on performance of the column. However, the amplitude of the residual stress which does not change in plate thickness direction has an impact on performance of the column. Secondly, followings were found from the analysis results where composite initial imperfections are introduced in the member. 4) The amplitude of the local imperfection is the most influential initial imperfection on the deformation capacity of the column, and the deformation capacity decreased with an increase of the amplitude of local imperfection. The influence of the amplitude of the global imperfection is insignificant on the deformation capacity. On the other hand, the amplitude of the global and local imperfection and the magnitude of the residual stress do not have significant impact on the maximum bending moment. 5) Validation of the numerical simulation were also performed; initial imperfections that can simulate test results in reasonable accuracy was shown.

著者

加來 千紘 長谷見 雄二 安井 昇 保川 みずほ 上川 大輔 亀山 直央 小野 徹郎 腰原 幹雄 長尾 博文

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.79, no.701, pp.1065-1072, 2014-07-30 (Released:2014-09-30)

参考文献数

18

被引用文献数

2 9

---

Young's modulus and bending strength of 3 species of wood commonly used for engineered wood and Zelkova, hardwood normally used for traditional large building, heated up to 250℃ are measured at the elevated temperature and after cooling to the room temperature as an engineering basis for the structural fire safety design and the reusability diagnosis of large-scale timber buildings. The results show the both properties, either at elevated temperature or after cooling, are highly dependent on exposed temperature for 150-200℃ or higher, and correlation between the Young's modulus and the bending strength tends to become weaker with rise of exposed temperature. The bending strength at elevated temperature is found to converge while it is notably scattered at normal temperature.

著者

加藤 史郎 庄村 昌明 向山 洋一

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.60, no.477, pp.87-96, 1995

参考文献数

20

被引用文献数

15 20

---

The present paper investigates the dynamic response of single layered reticular domes simultaneously subjected to horizontal and vertical earthquake motions. A dome which is assigned a safety factor ranging from two to four against the limit state for dead load is analyzed dynamically to the earthquake motions of Taft, El-centro and Miyagi-oki earthquakes. The collapse acceleration that is defined as the minimum acceleration enough to cause the dome to collapse is evaluated. For the dome with a safety factor of two, three and four, the collapse accelerations are found, respectively, 167, 473 and 778 gals. Based on the results, an formula to estimate the collapse acceleration is given by using the relative displacement response spectra for earthquake motions.

著者

藤澤 正視 垣見 俊弘

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.67, no.560, pp.109-114, 2002

---

Machu Picchu is undoubtedly the most famous ruins of the Inoa Empire. It is located northwest of Cuzco, the former capital of the Inca Empire, and east-southeast of Lima, the current capital of the Republic of Peru. The ruins are located at a narrow ridge (N15 W) between Mt. Machu Picchu (elev. 3060m) on the south and Mt. Huayna Picchu (elev. 2660m) on the north. The site has been investigated by a Japanese mission comprised of experts on archeology, city planning, structural engineering and seismic engineering, seismology, geology and soil engineering. The results of topographical and geological investigations of the site indicate: 1. Construction of the ruins took advantage of topographical conditions but large-scale reconstruction is not feasible. 2. The base rock of the site consists of granite. Insitu construction used materials from the local base rock. 3. Colluyial soils exist on gentle slopes. Current condition suggests that they were recently formed. ' 4. As long as there is not a great earthquake or especially heavy rainfall, there is little probability that serious damage will occur from the foundation.

著者

平井 宏幸 長谷見 雄二 安井 昇 木村 忠紀 山本 幸一

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.73, no.625, pp.489-495, 2008-03-30 (Released:2008-10-31)

参考文献数

5

---

Fire resistance tests have been conducted to develop wooden floor-beam assemblies of 45 minutes fire resistance for design loading conditions based on Japanese traditional post and beam construction. The tests were initiated with a 2m x 3m floor specimen consisting of six 1m x 1m small specimens of different specifications including four designs with beams exposed to the lower floor and two designs with ceiling panel beneath the beam to verify the integrity and thermal penetration through the floor panels. Beams to bear with the standard loading for domestic use and assemblies for 45 minutes standard fire exposure were then designed with the vertical deflection as the temporary index for compliance with the fire resistance standard. Large scale loaded fire tests were conducted on two designs, one with bare beam and another with ceiling panel, resulting in the achievement of 45 minutes prevention of flame and thermal penetration or buckling.

著者

武田 雄二

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.63, no.505, pp.31-36, 1998-03-30 (Released:2017-02-02)

参考文献数

8

被引用文献数

1 1

---

This paper aims at clarifying the general properties of ultraviolet (UV) ray reflection of building materials. Firstly, we analyze UV ray reflection photo of building and landscapes in an university campus. It is observed that the intensity of UV ray reflection varies among materials. Secondly, we measured reflection intensity and ratio of UV ray for 42 specimens of building materials, and then classified those materials into 6 groups using multidimensional scaling method. The findings show that the UV ray reflection properties depend largely on the absorption ratio of U V ray and on the shape and roughness of material surfaces.

著者

釜江 克宏 入倉 孝次郎

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.62, no.500, pp.29-36, 1997

参考文献数

30

被引用文献数

24 10

---

The 1995 Hyogo-ken Nanbu earthquake struck Kobe and adjacent cities, one of the most densely populated area in western Japan, and killed more than 6,400 people and destroyed more than 150,000 buildings and houses and tens of highway and railroad bridges. It is very important to examine the ground motion characteristics in the severely damaged area during the mainshock for understanding how buildings and bridges performed and why they reached collapse. Unfortunately very few strong ground motions were recorded in the severely damaged areas during the mainshock. In this study, we attempt to estimate ground motion at severely damaged sites by using the empirical Green's function method (EGF method). We derive a best source model with three asperities after several try and error with forward modeling by the EGF method. We estimate strong ground motions at sites, where the mainshock was not recorded, using aftershock records. The synthesized motions in the near-fault region in Kobe were characterized by two large long-period (1 to 3 seconds) pulses due to the forward rupture directivity. Peak horizontal acceleration and velocity of the synthesized motions at the heavily damaged sites are about 1,000 cm/sec^2 and 130 cm/sec, respectively, while those at a rock site in near-fault region show about 300 cm/sec^2 and 60 cm/sec. The reason why so strong motions hit the heavily damaged sites is that the large long-period pulses which come from two asperities in the Kobe-side segment of the fault were further amplified by the basin edge effects.

著者

小島 紘太郎 五月女 義人 竹脇 出

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.82, no.735, pp.643-652, 2017

被引用文献数

7

---

&nbsp;After Parkfield earthquake in 1966 and San Fernando earthquake in 1971, various aspects of near-fault ground motions have been clarified and the effect of near-fault ground motions on structural response have been investigated extensively. The fling-step and forward-directivity inputs have been characterized by two or three sinusoidal wavelets. For this class of ground motions, many sophisticated analyses have been conducted from various viewpoints. However, as far as a forced input is employed, both a free-vibration term and a forced-vibration term appear and the closed-form expression of the elastic-plastic response may be difficult. In order to overcome this difficulty, the double impulse has been introduced as a good substitute of the near-fault ground motion and the closed-form expression of the undamped elastic-plastic response of a structure under the critical double impulse has been derived in the previous works.<br>&nbsp;In this paper, the double impulse is introduced again and the closed-form solution of the maximum deformation of the elastic-perfectly plastic single-degree-of-freedom (SDOF) system with viscous damping under the &lsquo;critical double impulse&rsquo; is derived. Because only the free-vibration appears after each impulse of such double impulse, the energy approach plays an important role in the derivation of the closed-form solution of the maximum elastic-plastic response of the SDOF system with viscous damping. However, it is difficult to treat exactly both of hysteretic damping and viscous damping even in the theory using double impulse. The quadratic-function approximation for the damping force-deformation relationship and the assumption that the critical timing of the second impulse is characterized by the stage of the zero restoring force after the first impulse are introduced to derive the maximum elastic-plastic response with viscous damping by using the energy balance formulation.<br>&nbsp;The validity of the proposed theory using the quadratic-function approximation and the assumption of the critical impulse timing has been investigated through the comparison with the critical elastic-plastic response under double impulse using the time history response analysis. The validity of the proposed closed-form solution has also been demonstrated through the comparison with the response analysis to the corresponding one-cycle sinusoidal input as a representative of the fling-step near-fault ground motion. Furthermore, in order to investigate the applicability of the proposed theory to actual recorded ground motions, two recorded ground motions have been taken into account. It has been demonstrated that the maximum response to the critical double impulse and the response to the selected ground motion coincide fairly well. This supports the validity of the proposed theory.