Keywords

1 Introduction

At present, China is in a period of high incidence of earthquakes, and a series of social problems and urban development trends caused by earthquakes have also aroused widespread concern from government departments [1,2,3]. Communities are deductive of cities at a more accurate regional scale and therefore have common characteristics of exposure to different risks. The earthquake will lead to the destruction of community system. And then it can lead to the loss of life and property, the loss of community function, the imbalance of public order and a series of devastating consequences [4]. Experience shows that building collapse caused by earthquakes is the most important factor of causing damage. Therefore, evaluating the building and judging the risk level of the building will directly affect the safety of the life and property of the community residents and the stability and development of the community. Emergency preparedness is the key to earthquake disaster reduction and management. Higher emergency preparedness can effectively reduce losses caused by earthquakes and ensure sustainable urban development [5]. On the contrary, it will enlarge the damage of earthquake and increase the loss of disaster. The emergency preparedness ability before earthquake is the main factor to judge the effectiveness of impending emergency and disaster emergency work. In addition, the earthquake emergency preparedness of a special region is closely related to the local earthquake risk, vulnerability of buildings and population distribution. The higher the level of earthquake emergency preparedness, the lower the loss of life caused by earthquakes. Therefore, scientific analysis of earthquake emergency preparedness and earthquake risk level is of practical significance to improve the efficiency of earthquake emergency work and reduce casualties and property losses.

2 Case Study

Xinchengzi Community is located in the center of Shenbei New District, Shenyang city, Liaoning Province. And it is located in the North China earthquake zone, with nearly 50 faults over 5 km in length and nearly 30 faults over 10 km in length. It is an area with high fracture activity in the approach zone, and there are geological tectonic conditions for the occurrence of magnitude 5–6 destructive earthquakes. The buildings in Xinchengzi community are divided into four categories: multi-storey masonry houses, reinforced concrete houses, single-storey factory buildings and old houses (brick and wood houses and simple houses). Most of the buildings in Xinchengzi community are built before 2010. Most of the buildings are 3–6-storey structures, and most of them are multi-storey masonry buildings. It is assumed that the seismic fortification intensity of Shenyang city is VII, and the basic acceleration value is 0.10 cm/s2.

2.1 Seismic Risk Analysis of Xinchengzi Community

Vulnerability analysis curve

The building information in this paper is mainly based on the field research. At the same time, we have referred to “Shenyang New Area Seismic Environment Assessment”, “General Code for Masonry Structure” (GB55007-2021), “Code for Concrete Design” (GB50010-2010(2015 edition)), “Industrial Building reliability Identification Standard” (GB50144-2019), “Wood Structure Engineering Construction Quality Acceptance Code” (GB50206-2012) and other standards. Details as below:

Construction of dormitory building of Xinchengzi 83 Middle School

The dormitory building of Xinchengzi 83 Middle School is a multi-storey (five floors) masonry building. The total height of the building is 16.5 m, and the site category is class I. The walls are MU10 page rock bricks, the first and second floors are M10 cement mortar, and the third and above floors are M7.5 cement mortar. The wall thickness is 240 mm. The ring beam is layered, the cross section is 240 mm * 220 mm, the concrete grade is C25, and the building steel bar is HPB235 [6]. Strip rubble concrete is used. And the concrete is marked with C15, and the deep is 2.5 m.

Construction of Huamei Shopping Mall in Xinchengzi

Xinchengzi Huamei shopping mall is a reinforced concrete frame structure. The mall is a total of four layers, longitudinal depth of 4 m, 3 cross transverse opening, the bottom layer of 3.9 m, the other layer of 3.6 m, site category iii. The concrete strength grade of the frame beam and column is C30, the longitudinal reinforcement is HRB400, the stirrup is HPB235, the cross-section size of the frame beam is 250 mm * 500 mm, and the cross-section size of the frame column is 500 mm * 500 mm [7].

The basic seismic intensity of Xinchengzi subdistrict is VII degree, and the designed basic seismic acceleration value is 0.10 cm/s2. The buildings selected in this paper are modeled in 3D (see Fig. 1). The median value and standard deviation of buildings of the same type are found in HAZUS technical manual (see Table 1).

Table 1 Frailty curve \(S_{a,ds}\) and \(\beta_{ds}\)
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According to the vulnerability curve formula (1):

$${\text{P}}\left[ {d_{s} |S_{d} } \right] = \varphi \left[ {\frac{1}{{\beta_{ds} }}} \right]\ln \left( {\frac{{S_{d} }}{{S_{d,ds} }}} \right)$$
(1)

where \(d_{s}\) denotes degree of damage; \(S_{d}\) (instead of peak ground acceleration \(S_{a}\)) is the peak ground displacement; \(S_{d,ds}\) is the median value of peak ground acceleration borne by the disaster bearing body when it reaches the degree of failure \(d_{s}\); \(\beta_{ds}\) is the standard deviation of the natural logarithm of \(S_{d}\); \(\varphi\) is the standard normal distribution cumulative function.

The vulnerability curves of the three types of buildings are obtained by using Matlab program (See Fig. 1) (Fig. 2).

Fig. 1.
Two 3-D stereo views of the Xinchengzi 83 dormitory building and Xinchengzi Huamei shopping mall. The rectangular structures are made with lines.

3D stereo view of the building. Note 1 3D stereo diagram of Xinchengzi 83 dormitory building. 2 Three-dimensional stereo map of Xinchengzi Huamei Shopping Mall

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Fig. 2
Two line graphs plot exceedance probability versus P G A for light, medium, serious, and whole. Both graphs have an increasing trend.

Building vulnerability curve. Note 1 Fulnerability curve of multi-storey masonry houses. 2 Fulnerability curve of multi-storey reinforced concrete houses

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Determination of capability curve

Using the relevant parameters of the target determined in Sect. 2.1 and the Pushover function of Huzus software, the capability-demand spectrum curve of Xinchengzi community is draw and the performance points are obtained. In the figure, the green curve starting from the origin is the capability curve, and the red curve is the demand spectrum, as shown in Fig. 3. In which the abscissa is \(S_{d}\) and the ordinate is \(S_{a}\).

Fig. 3
2 screenshots of line graphs of spectral acceleration versus spectral displacement. The capability curve and demand spectrum have an increasing and decreasing trend, respectively. The revise option is highlighted.

Building performance point curve. Note (1) Performance point curve of Xinchengzi 83 dormitory building. (2) Performance point curve of Xinchengzi Huamei Shopping Mall

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Determination of performance points and damage probability

Figure 3 illustrates the XinChengZi 83 dormitory building performance points corresponding to \(S_{a} = 0.359\;{\text{cm}}/{\text{s}}^{2}\), \(S_{d} = 0.339\;m\); the Huamei market performance points corresponding to \(S_{a} = 0.144\;{\text{cm}}/{\text{s}}^{2}\), \(S_{d} = 0.137\;m\). According to the \(S_{a}\) value determined by the above performance points and the vulnerability curve, the vulnerability matrix of each building can be calculated according to Eq. (1), as shown in Table 2.

Table 2 Vulnerability matrix of each building
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According to this method, the ten buildings in each of the four types of buildings in Xinchengzi community are selected for damage probability calculation. And the average value is taken to determine the earthquake damage matrix of the four types of the buildings, as shown in Table 3.

Table 3 VII degree seismic vulnerability matrix of four kinds of buildings in Xinchengzi community
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3 Conclusions

Based on seismic risk analysis, HAZUS and Pushover methods are used to analyze the vulnerability of community buildings and personnel. The results of risk analysis can be used as the basis of disaster prevention and mitigation decision of relevant administrative departments, and the evaluation of emergency preparedness ability can effectively improve the ability and level of earthquake emergency management. The comprehensive analysis results of the two can help local governments grasp the current situation of emergency preparedness capacity, find the gap between ideal capacity and realistic demand, and provide direction and overall target for government departments to improve countermeasures.