Experimental research on Chinese antique buildings with dual-lintel-column joint of steel and composite structures

ABSTRACT In order to study the mechanical behavior of Chinese traditional style architecture dual-lintel-column joint, a typical Chinese traditional style architecture dual-lintel-column joint was selected as the model structure. Two specimens with viscous damper and one specimen without viscous damper were designed and tested under fast harmonic load. On the basis of experimental study, the key indexes of mechanical properties are analyzed, such as the load–displacement hysteretic curve of specimens and viscous damper, skeleton curve, and load-bearing capacity. The results indicate that mechanical properties of antique buildings dual-lintel-column subassemblages with steel and composite structures and viscous damper can significantly increase the mechanical properties. The hysteretic curve of the damping joint is plump. The descending phase of skeleton curves is smoother. The carrying capacity is increased by 13.9%–14.1%, and displacement ductility is increased by 13.0%–18.6%. The viscous damper and the dual-lintel-column subassemblages work together. They significantly improve the deformation performance of structures at the failure stage and enhance the collapse resistance of the structure. The study of traditional architecture can also provide valuable insights into the development of structural engineering and construction technology. Also, people can learn the wisdom and experience of ancestors and apply it to modern engineering practices.


Introduction
The architecture of China is the as old as Chinese civilization.From every source of information in literature, figures, and examples, there is strong evidence that the Chinese have always adopted native architectural system, and this structure has maintained its main characteristics from prehistory to the present day.Ancient Chinese buildings are mainly made of wood, and for thousands of years, they have experienced all sorts of earthquakes but remain intact.China's architecture highlights its local culture and history (Liang 1951(Liang , 1986)).These are the invaluable cultural and historical legacies of China.Now, with the advent of reinforced concrete and steel framing, accompanied by the rapid pace of urbanization in China, urban construction and transformation are also accelerating, Chinese architecture is facing significant challenge.Finding a balance between the structure of new cities and the characteristics of traditional architectural culture and regional culture is an essential topic for the present and future Chinese urban builders.
Chinese traditional architecture is a kind of exploration and innovation, which has a good prospect of popularization and application.Chinese traditional style architectures are similar to ancient Chinese structures in external appearance, but with respect to the materials, the force transmission mechanisms and seismic behaviors are quite different.Modern building materials (ie, concrete and steel) and construction technologies have been adopted in traditional Chinese structures, such as Xi'an Lou Guan Tai, shown in Figure 1(a), and Kaifeng Han Yuan, shown in Figure 1(b).
However, the structural mechanical properties and analytical methods are different from those of modern structures.In order to satisfy the seismic requirements of modern buildings while retaining their architectural characteristics, this paper studies the seismic performance of double-square-column structures with viscous dampers.
In recent years, many scholars have carried out a series of related studies on Chinese traditional style architecture, which mainly focus on improving the artistry, and related construction technology, structural (component) mechanical properties, and so on.Indeed, most research on the mechanical properties of the Chinese traditional style architecture is only in the beginning phase, and an integrated technical system has not been developed.At present, the research on traditional style architecture mostly focuses on its artistic and construction technology and other relatively basic parts, while the research on its mechanical properties is relatively lagging behind, and there is no systematic study according to certain characteristics such as shape and structure.
J. Xue, L. Zhai (2016); J. Xue, Z. Wu (2016); Xue, J. Dong, and Y. Sui (2017bSui ( , 2017a) ) carried out pseudostatic test study and shaking table test research of Chinese traditional style architecture with concrete structure and steel structure.The results showed that the steel structure and steel-concrete composite structure of Chinese traditional style architecture have good seismic performance; Sui, Xue, and J. Dong (2019); Sui, Xue, and Z. Wu (2018); Sui, Xue, and J. Dong ( 2017) conducted experiments on lintel-column joints in Chinese traditional style architecture under rapid sinusoidal reciprocating loads, demonstrating that the combination of viscous dampers and Chinese traditional style architecture concrete joints significantly improves their mechanical properties; Xie, Li, and H. Ge (2015); Xie, Li, and L. Wang (2014) analyzed concrete dual-lintel-column joint of Chinese traditional style architecture showing that its ductility coefficient is low and its seismic requirements do not meet the requirements of the current code.
There are less results in the typical dual-lintel-column joints in Chinese traditional style architecture.However, the dual-lintel-column joint has a large core area, and its mechanical performance and deformation characteristics are quite different from those of the conventional joint.Besides, the columns of antique architecture were mostly variable sections, and the section size of the upper column was smaller than that of the lower column, resulting in a sizeable axial compression ratio of the upper column.At the same time, they primarily adopted pseudo-static tests in the joint examination of Chinese traditional style architecture, which was different from mechanical properties of components under earthquake action.
Considering this, a steel-concrete composite structure with a viscous damper was employed as the upper column for testing dual-lintel-column joints in Chinese traditional-style architecture.Three typical test specimens were designed under rapid sinusoidal reciprocating loads.Their deformation performance and mechanical behavior were analyzed to provide a useful reference for the design of antique buildings in practical engineering.

Typical dual-lintel-column joint
The ancient timber structure adopted horizontal and vertical wooden frames as the load-bearing components, and dougong bracket sets are set in the column heads, and the dougong bracket sets are the main vertical force transmission components of the structure.However, the mechanical mechanism has been changed in Chinese traditional style architecture, the dougong bracket sets have been changed in column, and dougong bracket sets are no longer load-bearing components but only used as decorations.Presently, Chinese traditional style architecture are mostly the temple architecture, and the construction class of the Chinese traditional style architecture is generally divided into first or second class according to the ancient timber structure, as shown in Figure 2. The horizontal member, which is a rectangular crosssection, is called architrave.The rectangular cross-section beam be called architrave, cushion architrave and upper architrave, lower architrave in the Song and Qing dynasty, respectively.
The architrave is a horizontal member connecting and bearing the column.Most of them were placed on the top of the column in the Southern and Northern dynasties and were moved to the column after the Sui and Tang Dynasties.Sometimes the two are overlapping.In the Qing Dynasty, the above is called upper architrave (Song called Lan`e), and the following is called lower architrave (Song called You`e).The two were filled with a pad called cushion.Between the two filled with a pad called cushion architrave.
Compared with conventional beam-column joints, the dual-lintel-column joints have larger core area, which is divided into upper, middle, and lower core areas, as shown in Figure 2(b).The force mechanism and deformation characteristics are also significantly different from conventional beam-column joint.

Design summary of specimen
Three Chinese traditional style architectures with duallintel-column joints were designed for the tests, two specimens with viscous dampers (specimens DA-2 and DA-3) and a specimen without a viscous damper (specimen DA-1).Considering the ease of manufacture and the limitation of experimental conditions, the ratio of all specimens was 1/2.6.
The design details and geometric configuration of the tested specimens are shown in Figure 3(a) and (b), and the main part of the reinforcement device is also shown in Figure 3(c,b,e).Due to the variable crosssection of the column, the upper column is made of concrete-filled steel tubular, the steel is made of Q235B, and the sectional dimension of the steel is 160 mm ×160 mm with the thickness of 5.5 mm.The mechanical properties of steel members based on material testing are shown in Table 1.
In this study, all lintels and columns were made of grade C40 concrete with cube compressive strength of 43.1 MPa.Concrete fit is shown in Table 2.The ratio of axial compressive stress to strength is 0.25, and the measured strength of concrete determined vertical axial load.

Model selection and installation of damper
The velocity viscous damper was selected based on the experimental load characteristics, and the design parameters of damper are shown in Table 3. Basic design size parameters of the connection between viscous damper and specimen are shown in Figure 4 and Table 4. Figure 5 showed the installation drawing of visous damper, and the hinged connection between viscous damper and specimen was shown in Figure 6.The specimen DA-2 and DA-3 was installed the damper VD-1 and VD-2, respectively.In general, the load of viscous dampers is determined according to the regulations of wood structure of ancient buildings, called Caifen, and then the type and design parameters of viscous dampers can be determined according to the length of viscous dampers.Therefore, the change range of the main design parameters (such as viscosity coefficient and viscosity index) of the viscous damper can be selected according to the viscous damper provided by the manufacturer, and then the damper-related design parameters can be further selected according to the optimization results.

Experiment procedure
Figure 7 illustrates the experimental loading device, where the axes for the column and lintel are vertical and horizontal, respectively, with this configuration.The whole loading process is divided into two steps, the first step is the vertical compressive load was slowly applied on the top of the upper column using the 100 t hydraulic jack until the expected axial compression was reached, and the second step is the horizontal load of harmonic dynamic cyclic load was applied at the side edge of the upper column using MTS electro-hydraulic servo actuators with a range of 10 t.
Considering that a speed-nonlinear-relevant-type viscous damper was adopted for the specimens, the loading protocol was determined by controlling the displacement (amplitude) and loading frequency.Taking into account the dynamic and fatigue testing methods of the viscous damper, as well as the safety performance of the loading equipment, and cycled five times every loading conditions.The loading conditions of the experiment are shown in Table 5, and Figure 7 illustrates the loading conditions.In Figure 8, the interval of every loading condition is the observation time of test phenomenon after loaded of every loading condition.

Failure characteristic of specimens
According to the deformation and failure characteristics of each specimen during loading, the whole loading process is divided into four different stages.The Figure 9 and Figure 10 respectively illustrate the failure process and characteristics of the specimens in the absence or presence of a viscous damper.DA-1: (1) In the cracking stage (controlled displacement ≤ 11 mm), the restoring force curve of the specimen basically remained straight.At this stage, the number of cracks was relatively small on the whole and is mainly located in the connection between the You`e and the damper and the connection between the You`e and the column.The cracks were roughly parallel.(2) In the yield stage (15 mm ≤ control displacement ≤ 53 mm), with the increase of control displacement, the recovery force curve of the specimen appears an inflection point.The crack width increases, and new cracks appear.(3) In the limit stage (65 mm ≤ control displacement ≤ 88 mm), there is significant concrete spalling at the connection part of the specimen square column.Cracks in the core region are mainly distributed in the side diaphragm and the central area between the frontal.With the continuous increase of control displacement, cracks in this region are gradually connected.(4) In the failure stage (100 mm ≤ control displacement ≤ 115 mm), a large amount of concrete at the dual-lintel-column connection has been spalling, and there is a trend of further expansion.The width of the existing cracks is large, and the internal longitudinal bars can be seen.
When the angle between layers reached 1/38, the test ended, as shown in Figure 11.
DA-2 and DA-3: The failure process of DA-2 and DA-3 is basically the same, and DA-2 is used as an example for specific analysis.
(1) Cracking stage (control displacement ≤ 11 mm): the restoring force curve of the specimen presents linear characteristics.On the whole, the crack width is small, the length is short, and the main cracks are fine cracks.Compared with the specimen BD-1, there is little difference.
(2) Yield stage (15 mm ≤ control displacement ≤ 53 mm): the longitudinal reinforcement at the connection position of the dual-lintel-column yielded.The cracks of the specimen increased significantly, and the inclined cracks of about 45° were generated at the root of the upper column but no spalling of concrete was observed.
(3) Limit stage (65 mm ≤ control displacement ≤ 88 mm): the deformation of the specimen increases rapidly with the increase of the load, and the relationship between the two has been significantly non-proportional.When the specimen is unloaded to zero, there is a relatively significant residual deformation.The maximum load of the specimen gradually decreases with the increase of the number of cycles.(4) Failure stage (100 mm ≤ control displacement ≤ 115 mm): when the control displacement is 100 m, there is a crushing phenomenon of concrete in the core area, the crushing area is large, the depth is about 1.0 cm, the concrete at the beam-column connection is spalling a lot, and the stirrup and longitudinal reinforcement are obviously visible

Analysis of experimental results
Three specimens of Chinese dual-lintel-column joint have been done under the fast harmonic rapid- reversed loading test, and the relevant test data were measured.The test was terminated when the specimen DV-1 was loaded under loading condition 10 due to the specimen failure, and the other two specimens were loaded to loading condition 12.

Load-displacement hysteretic curves
Figure 11 shows the load-displacement hysteretic curves for the tested specimens, where P is the horizontal resistance and Δ is the corresponding horizontal displacement.
The load-displacement hysteretic curves of each specimen were plotted in a figure by selecting the first cycle of every loading condition, and then the as shown in Figure 12.Because the equipment cannot always be in a stable state in the loading process, the load-displacement curves have a certain floating.Although the hysteretic curve of the specimen shows a certain serrated shape, it can still objectively and comprehensively reflect the mechanical characteristics of the specimen.
From Figure 11, some main results could be obtained as follows: (1) No obvious signs of destruction at the initial loading stage at the beginning of the experiment (control displacement≤15 mm).Basically, the load-displacement hysteresis curve is strip distribution, and all specimens' load-displacement hysteresis curves' enveloped area was small.Meanwhile, under small control displacement, the slope of the curve that the ratio of horizontal resistance to corresponding horizontal displacement was lines relationship.Some small and irregular diagonal cracks in the lintel surface occurred as the horizontal displacement increasing.The cracking loads for all specimens are approximately equal, which indicated that viscous damper did not affect the crack-control performance greatly.
(2) There are some obvious characteristics for all specimen With the increase of control displacement, all samples have some obvious characteristics (15 mm <control displacement ≤ 65 mm).
Basically, the load-displacement hysteresis curve is not coincided with each other gradually, and the horizontal resistance of all specimens is no longer linear to the corresponding horizontal displacement.
(3) Meanwhile, at the same time, the degradation of strength and stiffness of all specimens was obvious with the small-scale concrete breaking, indicating that the specimens had entered the elastoplastic stage.The width and depth of the original crack at the first stage increased with the increase of the control displacement, and there are some other new diagonal cracks in the lintel surface that occurred with the increase of the control displacement.The main reason for this phenomenon is that the crack of the specimen appears and expands, the concrete breaks and spalling, and the steel bar enters the yield stage. (4) There are more obvious characteristics for all specimens at the later stage (65 mm < control displacement ≤ 115 mm), the load-displacement curve for specimen with viscous dampers had great deformation ability, and its bearing capacity was larger than that of the structure without viscous damper.
During the loading process, the shape of hysteresis loops gradually changes from arch to reverse "S" shape with the control displacement increases.( 5) Generally, it can be obtained from the above conclusion that installation of the damper could improve the bearing capacity of the specimen.The hysteresis curves for structure with viscous damper were plumper than those for structure without dampers, and the enveloped area of the curves was larger as well.
The results show that viscous dampers can significantly improve the mechanical properties and deformability of the Chinese traditional style architecture dual lintel-column joint, which provides the corresponding scientific basis for improving the seismic performance of the Chinese traditional style architecture in high seismic intensity area by adopted viscous dampers.

Load-displacement back-bone curves
Figure 12 shows the load-displacement back-bone curves for the tested specimens.The following results were obtained: (1) In the process of loading, the back-bone curve can be split up four stages: cracking stage, yield stage, limit stage, and failure stage.At the at the beginning of the loading stage, the back-bone curve of all specimens roughly overlapped, which indicate that there was no obvious difference in stiffness, which indicated that the installation of viscous dampers had no significant effect on the elastic working stage of small deformation of dual-lintelcolumn joint.With the control displacement gradually increases, the change tendency gradually shows great differences.On the whole, the stiffness and bearing capacity of specimens with viscous damper are superior to those of the contrast specimens without viscous damper, which indicated that damper can significantly improve the bearing capacity and lateral displacement resistance of the joint.
(2) Compared with the DA-2 and DA-3 specimens fitted with viscous dampers, the load of the backbone curve of DA-1 decreased more significantly after the peak.Combined with the analysis of experimental phenomenon, the specimen without viscous damper is the variable system with almost no bearing capacity.After the peak point, the specimen with viscous damper still has a certain bearing capacity.At the later stage of loading process, the damper can be used as a support to keep the structure is the unchanged system, which indicates that the collapse resistance and deformation performance of the specimen can be significantly improved by properly setting viscous damper at the joint between the front and the column (3) During the loading process, the back-bone curves can be divided into four stages: the crack stage, yield stage, ultimate state, and failure stage.However, there was no significant yield point in the back-bone curves, which reflects the gradual development of yield from the microcosm to the macrocosm.Based on the test results, the longitudinal steel rebar yield was considered the initiation of the yield stage.Furthermore, the bearing capacity of the specimen with viscous damper was significantly superior to that of the specimen without viscous damper.The addition of viscous dampers can significantly improve the bearing capacity and ductility.Therefore, combining viscous dampers with traditional Chinese buildings can be considered a better way to improve seismic performance and protect the main structure.

Analysis of bearing capacity and ductility
The bearing capacity and ductility behavior are the key indexes to represent the seismic properties of structures, especially the ductility behavior is the main embodiment of the residual bearing capacity and collapse resistance of structures after reaching the peak load.P m is the failure load, which is equal to 0.85P u , Δ m is the corresponding displacement of failure load.As shown in Figure 11, the ultimate load is defined as P u which means the peak load value of the back-bone curve.Through the equivalent elastic-plastic energy method we determine the yield load Py and yield displacement Δy.The ductility coefficient is the ratio of Δm to Δy.A computer-controlled data acquisition system was used to record all data from the load cell and actuator displacement sensor.The interlayer displacement angle is the ratio of the horizontal displacement of the column top on the specimen to the height of the specimen.
The load and displacement values of all specimens can be obtained by using the above methods.In order to make comparison and decision more convenient, histogram is selected to reflect the changing trend of load and displacement values.Some of the main results for the bearing capacity and deformation are listed in Tables 6, 7 and Figure 13.Draw the following conclusions: (1) By comprehensive comparison, the peak load arranged from high to low as DV-2, DV-3, DV-1.
Compared with structure without viscous damper DV-1, the peak load of structure with viscous damper was improved by 13.9% for DV-2 and 14.1% for DV-3, respectively.And the yielding load of controlled structure was improved by 15.3% for DV-2 and 16.2% for DV-3, respectively.The load and displacement for the yield point and ultimate point significantly increased for the joint with viscous damper.The results showed that viscous damper helped to improve the seismic performance of Chinese traditional style architecture dual-lintel-column joint under the elasto-plastic and plastic stages, implying that the viscous damper could better play its own effectiveness in highintensity area.
(2) By comprehensive comparison, the ductility coefficient arranged from high to low as DV-2, DV-3, DV-1.Compared with structure without viscous damper DV-1, the ductility coefficient of structure with viscous damper was improved by 18.6% for DV-2 and 13.0% for DV-3, respectively.Which shows that the viscous damper can improve the collapse resistance and deformation performance of dual-lintel-column joint structure, and effectively improve the performance of the structure in the area of high earthquake intensity.Actually, the dual-lintel-column joint with viscous damper can effectively reduce the magnitude of the uncoordinated deformation and uneven internal force distribution, At the same time, the global stability of the structure improved significantly.
(3) Under peak load, the interlayer displacement angle of all specimens represent obviously difference, the joint with viscous damper average reaching 0.96 times and 0.88 times of the joint without viscous damper values, respectively.Under failure load, the joint with viscous damper average reaching 0.83 times and 0.78 times of the joint without viscous damper values, respectively.The results meet the requirements of the existing code for elastic-plastic deformation and collapse resistance of structures, which indicated that the mechanical properties of the Chinese traditional style architecture can be greatly improved by adopting the steel-concrete composite structures and setting dampers at the suitable position.

Analysis of energy-dissipating capacity
By using equivalent damping coefficient h e and energy ratio I W (Gosain, Jirsa, and Brown 1977), we assessed the energy-dissipating capacity of Chinese traditional style architecture.In this part the yield ultimate and failure points are denoted by h ey , h eu , and h em , respectively.
The energy ratio at the failure point is expressed by IW.
The following results are obtained from Figure 13 and Table 8: (1) At the beginning of the experiment, the ratio of horizontal resistance and corresponding horizontal displacement was lines relationship under small control displacement.Compared with structure without viscous damper DV-1 under crack stage, the equivalent damping coefficients of structure with viscous damper was improved by 8.2 % for DV-2 and 9.4 % for DV-3, respectively, the energy consumption capacity increase is small.Due to the viscous damper has little influence on the mechanical properties of specimens before cracking, all specimens show low energy dissipation capacity.
(2) From the cracking stage to stage, the equivalent coefficient of all specimen increases in different degrees, which indicate that the energy capacity of the specimen increases gradually.the energy-dissipating capacity.Thus, it was possible to achieve the performance objective of no damage under medium seismic and reparability under severe earthquakes.
(3) The energy dissipation capacity of the specimens with viscous dampers are superior to those of the contrast specimens at all characteristic points, especially at the peak and failure points, which indicate that the viscous dampers can greatly improve the energy dissipation performance of Chinese traditional style architecture dual-lintel-column joint.Compared with structure without viscous damper DV-1 under point, the equivalent damping coefficients of structure with viscous damper was improved by 9.5 % for DV-2 and 16.8 % for DV-3, respectively.Generally, the energy ratios of specimens with viscous damper were better than those of contrast specimen, and all specimens were better than those of contemporary concrete members (Sivaselvan and Reinhorn 2000;Song and Pincheira 2000), which indicated that the Chinese traditional style architecture of steelconcrete composite structure had better ductility and adequate bearing capacity after the ultimate point.
To further study the influence of viscous damper on energy dissipation capacity of dual lintel-column joints, some quantificational indexes were adopted.The  enclosed area of load-displacement hysteretic loop for the 1, 3, and 5 cycled of all specimens under each loading condition was calculated, the result as shown in Figure 15.Meanwhile, the reduction coefficient of energy dissipation capacity, η, was defined as the area ratio of 1, 3, and 5 cycled between the 1 cycled, the result as shown in Figure 16.Some results can be obtained as follows.
(1) At the initial stage of loading process, the energy dissipation capacity of all specimens is low.After unloading, the specimen has no obvious residual deformation and no attenuation of strength and stiffness.With the increase of the control displacement, the area surrounded by the hysteretic curve of all specimen gradually increases, which indicate that the specimen has transitioned to the elastic-plastic stage and its energy dissipation capacity has been improved.(2) Compared with structure without viscous damper DV-1, the energy dissipation capacity of the specimen with viscous damper is superior to those of joint without viscous damper under each loading condition, which indicated that the mechanical properties of the Chinese traditional style architecture can be greatly improved by setting dampers at the suitable position, it was possible to achieve the performance objective of reparability under severe earthquakes.
(3) With the increase of the times of cycles, the area enclosed by the hysteresis curve gradually decreases.Taking the DV-3 under loading condition 6 as an example, the area ratio of the third and fifth hysteresis loop are 79.4% and 68.5% for the first hysteresis loop, respectively, which indicate that the reduction coefficient of energy dissipation capacity, η, are 79.4% and 68.5% respectively.The result demonstrated that with the increase of the control displacement, the energy dissipation capacity of specimens gradually decreases.

Analysis of stiffness
Stiffness degradation refers to the stiffness decreases with the increase in the times of cycles, while the control displacement remains unchanged during the reciprocating loading process, which is general use of the secant stiffness.The secant stiffness of each specimen during the 1st, 3rd and 5th cycles of each working condition was taken, and the calculation results were shown in Figure 17, and the stiffness variation of all specimens under different control displacements is shown in Figure 18, From the figures, some results were listed as follows: (1) In general, under constant control displacement, stiffness decreases with increasing number of cycles that means the stiffness degradation is affected by load cycles.On the one hand, under a constant control displacement, the stiffness decreases with the increase of the number of cycles.Compared with the first cycle, the stiffness in the third and fifth cycle of each loading condition decreased significantly, the stiffness of the first cycle and the stiffness of the third cycle degenerated most obviously, as indicated in Figure 17.On the other hand, as a result of rapid increase of rapid increase of elastic-plastic stage of damage accumulation, the stiffness degradation rate increased with the increase of displacement control is decreased obviously.Also, there is almost no further damage accumulation, the stiffness of the specimen is basically no longer greatly reduced.And when the specimen was severely damaged, the damage does not change significantly.
(2) The stiffness degraded rapidly at the beginning, and then the degradation slowed for joint with viscous damper, however, the stiffness degradation curve of joint without viscous damper represents the linear relationship, as shown in the red dotted lines in Figure 18 which indicated that the stiffness degeneration rate of the joint with viscous damper was slow after the first being fast.For the joint without viscous damper, the results show that viscous damper can improve the energy dissipation ability of the joint to a certain extent and suppress the stiffness degradation rate of the joint.

Analysis of bearing capacity
Reduction coefficient of bearing capacity, λ, refers to the ratio of the peak load in the last cycle and the peak load in the first cycle of the specimen under each loading condition.The calculated result is shown in Figure 19.
(1) With the increase of the control displacement, the bearing capacity of all specimen decreases gradually, and the larger the control displacement is, the more serious the bearing capacity of the specimen decreases.Taking the DV-3 under loading condition 12 as an example, the bearing capacity is 78.2% of the initial strength of the specimen, it shows that the damage accumulation of specimens increases gradually in the failure stage, and the ability of resisting external effects decreases gradually.
(2) Compared with structure without viscous damper DV-1, the reduction coefficient of bearing capacity of the specimen with viscous damper is inferior to those of joint without viscous damper under the late loading.The average reduction coefficient of bearing capacity of specimens DV-2 and DV-3 is 84.6% and 78.2% under loading condition 12, and the corresponding value of DV-1 is 74.5%,The results show that the dampers can slow down the bearing capacity attenuation of specimens.

Conclusion
(1) Using steel-concrete composite structure can significantly improve the mechanical properties of the Chinese traditional style architecture dual-lintel-column composite, and effectively reduce the axial compression ratio of the upper column.After the installation of the viscous damper, the ductility coefficient of the joint is increased by about 15.3%, the energy dissipation capacity is increased by about 33.2%, and the power ratio coefficient is increased by about 11.6%.On the whole, the mechanical properties of the joint are effectively improved, which provides a theoretical basis for the promotion and use of traditional style buildings in high-intensity areas.
(2) The bearing capacity of the Chinese traditional style architecture is greatly improved by set the viscous damper, the hysteresis curve is fuller, the deformation capacity and energy dissipation capacity are significantly increased, and the stiffness and strength attenuation are restrained to a certain extent.Therefore, in practical engineering, reasonable viscous dampers can effectively improve the seismic performance of Chinese traditional style architecture joints.

Design suggestion
(1) In practical engineering, the Chinese traditional style architecture columns are mostly variable sections.In order to reduce the axial compression ratio of the upper column, steel-concrete composite structure can be used to prevent shear failure of test piece under high axial compression ratio.
(2) Before selecting viscous damper, relevant theoretical analysis and numerical simulation optimization should be carried out according to the characteristics of the project to determine suitable viscous damper design parameters.

Figure 1 .
Figure 1.The project case of Chinese traditional style architecture.(a) Xi 'an Lou Guan Tai (style of Tang dynasty).(b) Kaifeng Han Yuan (style of Song dynasty).

Figure 2 .
Figure 2. Sketch of dual lintel-column joint.(a) Chinese antique buildings.(b) The component of dual lintel-column joint.(c) The case of dual lintel-column joint.(d) Sketch of dual lintel-column joint.

Figure 3 .
Figure 3. Schematic diagram of connection between viscous damper and specimen.

Figure 4 .
Figure 4. Schematic diagram of connection between viscous damper and specimen.

Figure 6 .
Figure 6.Installation drawing of hinged connection betweenviscous damper and specimen.

Figure 15 .
Figure 15.energy of specimen under the test loading mode.

Figure 16 .Figure
Figure 16.coefficient of total energy consumption of specimen under the test loading mode.

Table 1 .
Mechanical properties of steel members for specimens.
y -yield strain, f y -ultimate strength, E s -elasticity modulus.

Table 2 .
Proportions of concrete mix.

Table 3 .
Design parameter of viscous damper.

Table 4 .
Basic design dimension parameters of the connection between viscous damper and specimen.
Note; a, b -horizontal projection length and vertical height of damper; θangle between damper and column; L -damper length; L b , L h -the hinged shoe height of the damper.

Table 5 .
The loading conditions of experiment.

Table 6 .
Characteristic loads and displacement values.

Table 8 .
Index of energy dissipation.