On the use of a simple tuned mass damper model for reducing the excessive vibration of tsunami evacuation suspension footbridge

constructions method is relatively simple compared to other the construction cost also becomes relatively cheaper. may be applied to construct span, slender and moderate the induce moving load such as pedestrian and motorcycle will seriously unsafe when the footbridges are used for tsunami evacuating to the safe zone, in Padang city area. In this study, a simple kind of excessive vibration of the suspension footbridge mentioned above. The of the mass concrete and used computer code based on the finite element method has shown the promising results. The excessive vibration of the is shown by the reduction of the vertical deformation of the suspension footbridge up to more than 90% compared to suspension footbridge without TMD. using the Batang Arau in Padang city , a river located in southern of suspension footbridge is relatively cheaper types of bridges. The construction method footbridge is also more simple when it other types of the bridges in g suspension constructed without proper detail . as the pedestrian Thus, it may become the danger in such : febrin@eng.unand.ac.id , Jafril Tanjung ent, Andalas University, The suspension footbridges are commonly constructed in the rural area. The


Introduction
The Padang city in West Sumatra, Indonesia, is predicted to experience major earthquakes and tsunamis in the near future. In Padang city, the evacuation roads often have to cross the river, while the number of the existing bridges are limited. For instance Padang city, namely Batang Arau, has only three bridges, two of them are footbridges, as shown in Figure 1. Its river draws the line between the populated area and the evacuation area in Gunung Padang. The cost for constructing kind of the compare other for the suspension compares to Moreover, the have been commonly engineering design. Thus, this bridge may be categorized as non-engineering bridges. The suspension footbridges is weight is moderate footbridges are prone to successive vibration induced by moving load such movements.

Introduction
The Padang city in West Sumatra, Indonesia, is predicted to experience major earthquakes and tsunamis in the near future. In Padang city, the evacuation roads often have to cross the river, while the number of the existing bridges are limited. For instance, a river located in southern of Padang city, namely Batang Arau, has only three bridges, two of them are footbridges, as shown in Figure 1. Its river draws the line between the populated area and the evacuation ung Padang. The cost for constructing the suspension footbridge is relatively cheaper compare other types of bridges. The construction method suspension footbridge is also more simple when it compares to other types of the bridges in g Moreover, the suspension commonly constructed without proper detail engineering design. Thus, this bridge may be categorized engineering bridges. The suspension footbridges is weight is moderate. footbridges are prone to successive vibration induced by moving load such as the pedestrian . Thus, it may become the danger in such Corresponding author: febrin@eng.unand.ac.id use of a simple tuned mass damper model for reducing the excessive vibration of tsunami evacuation suspension footbridge ,* , Jafril Tanjung Civil Engineering Department, Andalas University, Abstract. The suspension footbridges are commonly constructed in the rural area. The constructions method is relatively simple compared to other the construction cost also becomes relatively cheaper.
be applied to construct span, slender and moderate the induce moving load such as pedestrian and motorcycle will seriously unsafe when the footbridges are used for tsunami evacuating to the safe zone, in Padang city area. In this study, a simple kind of excessive vibration of the suspension footbridge mentioned above. The mass concrete and used computer code based on the finite element method has shown the promising results. The excessive vibration of the analytical is shown by the reduction of the vertical deformation of the suspension footbridge up to more than 90% compared to suspension footbridge without TMD. using the current proposed TMD Batang Arau in Padang city The Padang city in West Sumatra, Indonesia, is predicted to experience major earthquakes and tsunamis in the near future. In Padang city, the evacuation roads often have to cross the river, while the number of the existing bridges , a river located in southern of Padang city, namely Batang Arau, has only three bridges, two of them are the type of footbridges, as shown in Figure 1. Its river draws the line between the populated area and the evacuation ung Padang. The cost for constructing footbridge is relatively cheaper bridges. The construction method footbridge is also more simple when it other types of the bridges in g suspension footbridges in the rural area constructed without proper detail engineering design. Thus, this bridge may be categorized engineering bridges. The construction of the suspension footbridges is often long, slend . Therefore, footbridges are prone to successive vibration induced by as the pedestrian t may become the danger in such febrin@eng.unand.ac.id use of a simple tuned mass damper model for reducing the excessive vibration of tsunami evacuation suspension footbridge Tanjung 1 , and Syah Bintang ent, Andalas University, The suspension footbridges are commonly constructed in the rural area. The constructions method is relatively simple compared to other the construction cost also becomes relatively cheaper.
be applied to construct its type of span, slender and moderate weight, the the induce moving load such as pedestrian and motorcycle will seriously unsafe when the footbridges are used for tsunami evacuating to the safe zone, in Padang city area. In this study, a simple kind of excessive vibration of the suspension footbridge mentioned above. The mass concrete and used the motorcycle or light car computer code based on the finite element method has shown the promising results. The excessive analytical model of the is shown by the reduction of the vertical deformation of the suspension footbridge up to more than 90% compared to suspension footbridge without TMD. current proposed TMD is recommended to be u Batang Arau in Padang city.
The Padang city in West Sumatra, Indonesia, is predicted to experience major earthquakes and tsunamis in the near future. In Padang city, the evacuation roads often have to cross the river, while the number of the existing bridges , a river located in southern of Padang city, namely Batang Arau, has only three the type of suspension footbridges, as shown in Figure 1. Its river draws the line between the populated area and the evacuation high land ung Padang. The cost for constructing such footbridge is relatively cheaper bridges. The construction method footbridge is also more simple when it other types of the bridges in general.
footbridges in the rural area constructed without proper detail engineering design. Thus, this bridge may be categorized construction of the long, slender and the the suspension footbridges are prone to successive vibration induced by as the pedestrian and motorcycle t may become the danger in such The suspension footbridges are commonly constructed in the rural area. The constructions method is relatively simple compared to other the construction cost also becomes relatively cheaper.
of the suspension weight, the footbridge construction has excessive vibration caused by the induce moving load such as pedestrian and motorcycle will seriously unsafe when the footbridges are used for tsunami evacuating to the safe zone, in Padang city area. In this study, a simple Tuned Mass kind of excessive vibration of the suspension footbridge mentioned above. The the motorcycle or light car computer code based on the finite element method has shown the promising results. The excessive model of the suspension footbridge is shown by the reduction of the vertical deformation of the suspension footbridge up to more than 90% compared to suspension footbridge without TMD.
is recommended to be u The Padang city in West Sumatra, Indonesia, is predicted to experience major earthquakes and tsunamis in the near future. In Padang city, the evacuation roads often have to cross the river, while the number of the existing bridges , a river located in southern of Padang city, namely Batang Arau, has only three suspension footbridges, as shown in Figure 1. Its river draws the line high land such footbridge is relatively cheaper bridges. The construction method footbridge is also more simple when it eneral. footbridges in the rural area constructed without proper detail engineering design. Thus, this bridge may be categorized construction of the er and the suspension footbridges are prone to successive vibration induced by and motorcycle t may become the danger in such moving of the evacuees when evacuating to safe zone in the southern part of Padang city. on the Batang Arau limitation of the number of the bridges crossing Easy features of the community order to reduce the successive vibration indu moving The suspension footbridges are commonly constructed in the rural area. The constructions method is relatively simple compared to other types of the construction cost also becomes relatively cheaper. Therefore, the community suspension footbridges. Unfortunately, due to their long construction has excessive vibration caused by the induce moving load such as pedestrian and motorcycle movements will seriously unsafe when the footbridges are used for tsunami evacuating to the safe zone, ass Damper (TMD) kind of excessive vibration of the suspension footbridge mentioned above. The the motorcycle or light car spring. The computer code based on the finite element method has shown the promising results. The excessive footbridge is significantly is shown by the reduction of the vertical deformation of the suspension footbridge up to more than 90% compared to suspension footbridge without TMD. The type of suspen is recommended to be used in the tsunami moving of the evacuees when evacuating to safe zone in the southern part of Padang city. Constructing on the Batang Arau limitation of the number of the bridges crossing Easy, fast and low cost constructing are the main features of this type the suspension footbridge community-based order to reduce the successive vibration indu moving load, a simple The suspension footbridges are commonly constructed in the rural area. The types of bridges, thus as consequence, he community-based construction footbridges. Unfortunately, due to their long construction has excessive vibration caused by movements. This condition, however, will seriously unsafe when the footbridges are used for tsunami evacuating to the safe zone, (TMD) is proposed to reduce such kind of excessive vibration of the suspension footbridge mentioned above. The TMD The dynamic analysis by using the computer code based on the finite element method has shown the promising results. The excessive is significantly reduce is shown by the reduction of the vertical deformation of the suspension footbridge up to more than The type of suspension footbridge which sed in the tsunami-prone area such as moving of the evacuees when evacuating to safe zone in the southern part of Padang city. addition of the on the Batang Arau are recommended to overcome the limitation of the number of the bridges crossing and low cost constructing are the main type of the suspension footbridge suspension footbridge based construction order to reduce the successive vibration indu , a simple mage of Batang Arau

use of a simple tuned mass damper model for reducing the excessive vibration of tsunami evacuation
The suspension footbridges are commonly constructed in the rural area. The bridges, thus as consequence, based construction footbridges. Unfortunately, due to their long construction has excessive vibration caused by . This condition, however, will seriously unsafe when the footbridges are used for tsunami evacuating to the safe zone, such as is proposed to reduce such TMD is composed dynamic analysis by using the computer code based on the finite element method has shown the promising results. The excessive reduced. Its reduction is shown by the reduction of the vertical deformation of the suspension footbridge up to more than sion footbridge which prone area such as for moving of the evacuees when evacuating to safe zone in the southern part of Padang city. the suspension are recommended to overcome the limitation of the number of the bridges crossing and low cost constructing are the main suspension footbridge suspension footbridge may be conducted construction without difficulty order to reduce the successive vibration indu mage of Batang Arau (Source: Google Maps)

use of a simple tuned mass damper model for reducing the excessive vibration of tsunami evacuation
The suspension footbridges are commonly constructed in the rural area. The bridges, thus as consequence, based construction footbridges. Unfortunately, due to their long construction has excessive vibration caused by . This condition, however, such as is proposed to reduce such composed dynamic analysis by using the computer code based on the finite element method has shown the promising results. The excessive ts reduction is shown by the reduction of the vertical deformation of the suspension footbridge up to more than sion footbridge which for moving of the evacuees when evacuating to high land safe zone in the southern part of Padang city. suspension footbridges are recommended to overcome the limitation of the number of the bridges crossing it river. and low cost constructing are the main suspension footbridge. Thus, may be conducted in without difficulty. In order to reduce the successive vibration induced by the . The TMD was assembled from mass concrete and the motorcycle or light car analytical study has been addressed suitably in the design cycle as well as in the safe assessment of this suspension footbridge purpose, the computer based on the dynamic element method, SAP2000, TMDs have been bration of the civil structures heavy load and hi-vibrate railway bridges. The comprehensive discussed has been well-documented Shetty et.al. [2] and Mehrabi et.al. [3].
, easy to apply and simple construction, the s, recently, often used to vibration of the existing pedestrian bridge structures Chen  properties. proposed in this . The TMD was assembled from mass concrete and series of has been addressed suitably in the ty and comfort . For this finite used for reduction y used such as it topic by Latifi and Razani [1], Due to its apply and simple construction, the reduce the successive as well as the By analytical study, as well as when evaluating the effects of the TMD to the dynamic considered suspension footbridge structure. The was analysed by using commercial computer software based on the finite element method, i.e. SAP2000. In the analysis, all the materials used in the suspension footbridge model were assumed to be homogeneous elastic linear materials as are tabulated i were performed to evaluate the performance of the TMD analysis was conducted due to applied moving load Three have been moving load was applied when the load entering and leaving the footbridge, while the second move along the span of the footbridge. responses of th integrating using integration parameters  simple prepared. One model without TMD (WO) and three models were used TMD, i.e. bottom of the bottom of the bottom of the (WCQ). The matrix of this analytical works is tabulated in Table 2.

Modulus
Analytical model of suspension footbridge. Figure 1. shows an analytical model of currently considered suspension footbridge structure. The was analysed by using commercial computer software based on the finite element method, i.e. SAP2000. In the analysis, all the materials used in the suspension footbridge model were assumed to be homogeneous elastic linear materials as are tabulated i The linear elastic modal were performed to evaluate the performance of the TMDs in the suspension footbridge. analysis was conducted due to applied moving load Three types of the moving loads have been defined moving load was applied when the load entering and leaving the footbridge, while the second move along the span of the footbridge. responses of the analytical model were obtained by integrating the equation of motion using the available integration parameters and  In order to evaluate the performance of the current simple proposed prepared. One model without TMD (WO) and three models were used TMD, i.e. bottom of the center span of the footbridge (WC), bottom of the quarter bottom of the center and quarter (WCQ). The matrix of this analytical works is tabulated in Table 2.  Figure 1. shows an analytical model of currently considered suspension footbridge structure. The was analysed by using commercial computer software based on the finite element method, i.e. SAP2000. In the analysis, all the materials used in the suspension footbridge model were assumed to be homogeneous elastic linear materials as are tabulated i elastic modal were performed to evaluate the performance of the suspension footbridge. analysis was conducted due to applied moving load types of the moving loads defined for this purpose. moving load was applied when the load entering and leaving the footbridge, while the second move along the span of the footbridge. e analytical model were obtained by the equation of motion available Hilber-Hughes integration parameters were taken as follow, . In order to evaluate the performance of the current proposed TMD, four analytical models have been prepared. One model without TMD (WO) and three models were used TMD, i.e. center span of the footbridge (WC), quarter span of the footbridge (WQ) and at center and quarter (WCQ). The matrix of this analytical works is tabulated  Figure 1. shows an analytical model of currently considered suspension footbridge structure. The was analysed by using commercial computer software based on the finite element method, i.e. SAP2000. In the analysis, all the materials used in the suspension footbridge model were assumed to be homogeneous elastic linear materials as are tabulated in Table 1. elastic modal and time history were performed to evaluate the performance of the suspension footbridge. The time history analysis was conducted due to applied moving load types of the moving loads, as it is shown in Fig. 2, for this purpose. The moving load was applied when the load entering and leaving the footbridge, while the second and third move along the span of the footbridge. The dynamic e analytical model were obtained by the equation of motion in the time Hughes-Taylor method were taken as follow, In order to evaluate the performance of the current TMD, four analytical models have been prepared. One model without TMD (WO) and three models were used TMD, i.e. was attached center span of the footbridge (WC), of the footbridge (WQ) and at center and quarter span of the footbridge (WCQ). The matrix of this analytical works is tabulated  Figure 1. shows an analytical model of currently considered suspension footbridge structure. The model was analysed by using commercial computer software based on the finite element method, i.e. SAP2000. In the analysis, all the materials used in the suspension footbridge model were assumed to be homogeneous n Table 1. time history analyses were performed to evaluate the performance of the The time history analysis was conducted due to applied moving loads.
, as it is shown in Fig. 2, The first type of moving load was applied when the load entering and and third types The dynamic e analytical model were obtained by the time domain by Taylor method. The were taken as follow, , In order to evaluate the performance of the current TMD, four analytical models have been prepared. One model without TMD (WO) and others was attached at the center span of the footbridge (WC), at of the footbridge (WQ) and at of the footbridge (WCQ). The matrix of this analytical works is tabulated analytical study.

WC
WQ WCQ Figure 1. shows an analytical model of currently model was analysed by using commercial computer software based on the finite element method, i.e. SAP2000. In the analysis, all the materials used in the suspension footbridge model were assumed to be homogeneous s were performed to evaluate the performance of the The time history . , as it is shown in Fig. 2, first type of moving load was applied when the load entering and s The dynamic e analytical model were obtained by domain by The , In order to evaluate the performance of the current TMD, four analytical models have been others at the at of the footbridge (WQ) and at of the footbridge (WCQ). The matrix of this analytical works is tabulated The proposed follow. The mass of TDM was taken about weight of the footbridge, exclude the pylon. of the TDM was of a first mode shape of the analytical model, multiply by the mass of the footbridge. the current proposed TDM is given in Table 3. SAP2000 computer software, the TDM is modeled as a LINK with Damper Friction Spring proposed TDM in this study was designed as e mass of TDM was taken about weight of the footbridge, exclude the pylon. of the TDM was defined as the square of the frequency of a first mode shape of the analytical model, multiply by the mass of the footbridge. the current proposed TDM is given in Table 3. SAP2000 computer software, the TDM is modeled as a LINK with Damper Friction Spring TDM in this study was designed as e mass of TDM was taken about weight of the footbridge, exclude the pylon.
defined as the square of the frequency of a first mode shape of the analytical model, multiply by the mass of the footbridge. The resumed the current proposed TDM is given in Table 3 TDM in this study was designed as e mass of TDM was taken about 4% the total weight of the footbridge, exclude the pylon. The stiffness defined as the square of the frequency of a first mode shape of the analytical model, multiply resumed properties of the current proposed TDM is given in Table 3. SAP2000 computer software, the TDM is modeled as a [10]. 1 2 3 TDM in this study was designed as the total The stiffness defined as the square of the frequency of a first mode shape of the analytical model, multiply roperties of the current proposed TDM is given in Table 3. In SAP2000 computer software, the TDM is modeled as a

Analysis
Modal analysis eigen frequency of structure and corresponding mode shapes. From the modal analysis vibration of obtained. of the first the proposed TMD is shown in Fig. 3. used for TMD, i.e. 25 cm, was defined based on the accumulation of the maximum amplitude of the TMD and th

Analysis results and discussion
Modal analysis igenvalue analysis, which was frequency of structure and corresponding mode shapes. rom the modal analysis vibration of the obtained. As it was mentioned above that t of the first mode the stiffness of the proposed TMD is shown in Fig. 3. used for TMD, i.e. 25 cm, was defined based on the accumulation of the maximum amplitude of the TMD and the free space on the TMD. The excellent performance of the proposed TMD is also exposed by the comparison of the images first mode shape of vibration of all analytical models as it is shown in Fig. 4. The footbridge swing more excessive compared to others footbridges attached the proposed TMDs. history analysis was carried out due to applied moving load along the span of the footbridge dynamic responses i along the span of the analytical model of is shown in Fig. the vertical deformation downward direction.

results and discussion
Modal analysis was conducted based on linear value analysis, which was frequency of structure and corresponding mode shapes.
rom the modal analysis in this study the suspension foot As it was mentioned above that t mode was used in calculating the stiffness of the TMD. The schematic image of the proposed TMD is shown in Fig. 3. used for TMD, i.e. 25 cm, was defined based on the accumulation of the maximum amplitude of the TMD e free space on the TMD.
The excellent performance of the proposed TMD is also exposed by the comparison of the images first mode shape of vibration of all analytical models as it is shown . The footbridge without TMD vibrate was swing more excessive compared to others footbridges attached the proposed TMDs. history analysis was carried out due to applied moving along the span of the footbridge dynamic responses in the term of along the span of the analytical model of is shown in Fig. 5. A minus sign in the vertical deformation downward direction.

Unit
Hz kg kg/m 2 results and discussion conducted based on linear value analysis, which was used to find the natural frequency of structure and corresponding mode shapes.
in this study, twelve modes of suspension footbridge structure were As it was mentioned above that t used in calculating the The schematic image of the proposed TMD is shown in Fig. 3. Length of the used for TMD, i.e. 25 cm, was defined based on the accumulation of the maximum amplitude of the TMD e free space on the TMD.
. The excellent performance of the proposed TMD is also exposed by the comparison of the images first mode shape of vibration of all analytical models as it is shown without TMD vibrate was swing more excessive compared to others footbridges attached the proposed TMDs. The linear elastic time history analysis was carried out due to applied moving along the span of the footbridge. Comparison of n the term of vertical deformation along the span of the analytical model of each footbridge A minus sign in the curve indicates the vertical deformation downward direction. , twelve modes of bridge structure were As it was mentioned above that the frequency used in calculating the mass and The schematic image of the Length of the spring used for TMD, i.e. 25 cm, was defined based on the accumulation of the maximum amplitude of the TMD The excellent performance of the proposed TMD is also exposed by the comparison of the images first mode shape of vibration of all analytical models as it is shown without TMD vibrate was swing more excessive compared to others footbridges The linear elastic time history analysis was carried out due to applied moving Comparison of vertical deformation each footbridge the curve indicates the vertical deformation downward direction.
conducted based on linear used to find the natural frequency of structure and corresponding mode shapes.
, twelve modes of bridge structure were he frequency mass and The schematic image of the spring used for TMD, i.e. 25 cm, was defined based on the accumulation of the maximum amplitude of the TMD The excellent performance of the proposed TMD is also exposed by the comparison of the images first mode shape of vibration of all analytical models as it is shown without TMD vibrate was swing more excessive compared to others footbridges The linear elastic time history analysis was carried out due to applied moving Comparison of vertical deformation each footbridge the curve indicates  The comparison of analytical results has shown the superiority of the proposed TMD for reducing the vertical deformation along the span of the footbridge. An optimum position of TMD was obtained at the quarter span of the footbridge,

Conclusion
The analytical study for evaluating the proposed simple TMD has been conducted and discussed in this paper. The proposed simple TMD is composed of the mass concrete and used the motorcycle or light car springs. The analytica the finite element method, SAP2000, show that the proposed simple TMD succeeds to reduce the vibration induced by the moving load. TMD has significantly reduced the natural frequency and vertical deformation of the analytical model of the suspension footbridge. that the attached the TDM on the quarter span of the suspension footbridge to reduce it excessive vibration. Final proposed TMD is recommended to be used of suspension footbridge prone area such as for Batang Arau in Padang city.
The comparison of analytical results has shown the superiority of the proposed TMD for reducing the vertical deformation along the span of the footbridge. An optimum position of TMD was obtained at the quarter span of the footbridge, i.e. the WQ model.

Conclusion
The analytical study for evaluating the proposed simple TMD has been conducted and discussed in this paper. The proposed simple TMD is composed of the mass concrete and used the motorcycle or light car springs. The analytical results by using computer code based on the finite element method, SAP2000, show that the proposed simple TMD succeeds to reduce the vibration induced by the moving load. TMD has significantly reduced the natural frequency and vertical deformation of the analytical model of the suspension footbridge. The analytical study also shows attached the TDM on the quarter span of the suspension footbridge has been given to reduce it excessive vibration. Final proposed TMD is recommended to be used of suspension footbridge prone area such as for Batang Arau in Padang city.