Tam Larkin - Academia.edu (original) (raw)
Papers by Tam Larkin
2022 Wireless Power Week (WPW)
Journal of the Geotechnical Engineering Division, 1981
Proceedings of the 4th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2013), 2014
Building pounding, defined as the earthquake induced collision between insufficiently spaced buil... more Building pounding, defined as the earthquake induced collision between insufficiently spaced buildings, has been recognized as a recurring urban seismic hazard. Numerous studies have been carried out in the past decades on the severity of the hazard. Most of the studies employ a contact force approach, where an elastic or viscoelastic link is placed between the colliding masses in series with a gap. The link is activated when the gap is closed and the pounding force is calculated from the deformation, and rate of change of deformation of this link. Several numerical models have been proposed to compute the pounding force. Past studies have compared the performance of these models in predicting force due to the impact of a sphere falling on a floor or a beam. However, building pounding is the collision of distributed masses i.e. slabs or beams of structures and few such experimental results exist. This study presents the force due to the pounding of two suspended reinforced concrete ...
In all major earthquakes, structures in the proximity of rivers and coastal plains, are often aff... more In all major earthquakes, structures in the proximity of rivers and coastal plains, are often affected by substantial excess pore-water pressure which may lead to soil liquefaction. The excess pore-water pressure will lead to soil softening and change in structural response. However, in the few cases where soil-structure interaction is considered during the analysis process almost always a linear model of the soil and structure is employed. While this model is simple and therefore convenient, the analyses are a poor representation of real soil behaviour. Additionally, in major urban areas most structures are closely adjacent. Therefore, the situation is more complex than free-field condition or just a stand-alone structure. The analysis of a single structure cannot capture the major characteristics of the seismic response of closely adjacent structures. In this work an elasto-plastic multi-mechanism model was used to represent soil behaviour. A coupled solid-liquid phase formulation...
Compacted fill soils in hillside areas for residential dwellings are becoming prevalent as develo... more Compacted fill soils in hillside areas for residential dwellings are becoming prevalent as development within New Zealand continues to expand. Many of these sites are located on tectonically active areas, and hence the seismic performance of such earth structures should be given due consideration. The current earth fill construction standard in New Zealand (NZS 4431:1989) provides only brief mention and no guidance regarding the seismic stability of hillside fills. Consequently, revisions to the New Zealand earth till construction standard are warranted and urgently needed. In this paper, the principal seismically-induced ground deformation mechanisms (i.e., landslides and seismic compression) in hillside fills are identified, and some existing analysis procedures are summarized. Lastly, some considerations for future New Zealand earth fill construction practices are provided.
Extensive deposits of pumice sand are found in various parts of the North Island of New Zealand, ... more Extensive deposits of pumice sand are found in various parts of the North Island of New Zealand, and their soft grained nature raises questions about their engineering properties. This paper describes an investigation of the basic properties of such a sand. The first part of the investigation involves laboratory measurements of compressibility and strength, and the second part looks at penetrometer resistance using a calibration chamber. Parallel tests on the pumice sand and a quartz sand are conducted in each case. The results are surprising. The values of the two sands are almost identical, although the pumice sand has higher compressibility. The penetrometer resistance of the pumice sand is almost independent of relative density, and only moderately influenced by confining stress. Conventional correlations between cone resistance and relative density are clearly not applicable to the pumice sand.
During past decades the destructive potential and the complexity of soil liquefaction phenomenon ... more During past decades the destructive potential and the complexity of soil liquefaction phenomenon associated with strong earthquakes has been widely documented. However, current structural seismic design generally neglects the influence of the subsoil. Design codes that deal with liquefaction usually focus the settlements that can affect the structural foundations. Additionally, most studies related to soil-structure interaction have focused on the response of an isolated structure. In reality, especially in urban areas, this assumption rarely can be justified. The omission of adjacent structures can lead to inaccurate results, especially when nonlinear behaviour of soil, e.g. resulting from liquefaction, takes place. The aim of this work was to implement a holistic approach to the study of liquefaction. The influence of an existing structure on the liquefaction potential will be presented. Also, the effects of adjacent structures on the seismic response will be investigated under co...
Earthquake Engineering & Structural Dynamics, 2021
This research addresses the influence of the load characteristics, that is, frequency content and... more This research addresses the influence of the load characteristics, that is, frequency content and maximum acceleration, on the wall stresses of an anchored water storage tank. A low‐density polyethylene tank with a range of six different aspect ratios (water height to tank radius) was tested using a shake table. Eight sine excitations that cover the lowest free vibration frequency of the tank‐water system were applied. Additionally, two sets of five Ricker wavelet excitations were utilized. Each set represents potential earthquakes with a bandwidth between a low and a high dominant frequency. The experimentally determined maximum stresses and those obtained from calculations using a common spring‐mass model employed for seismic analysis of tanks were compared. The results reveal that the relationship between the excitation frequency and the wall stresses strongly depends on the sloshing behavior, especially when the frequency of loading is in the vicinity of the lowest free–vibration frequency of the tank–water system. When the frequencies are dissimilar, there is a proportional relationship between stress and the maximum acceleration of the excitation. The spring‐mass model was found to underestimate both the maximum hoop stress (for aspect ratios greater than two) and axial stress (for aspect ratios equal to 0.5). This occurs because is the spring‐mass model cannot capture, in all cases, the contribution of chaotic sloshing to wall stress.
Geophysical Journal International, 2017
Bulletin of the New Zealand Society for Earthquake Engineering, 1994
This report describes the observations and assessments of the team members on the effects of the ... more This report describes the observations and assessments of the team members on the effects of the earthquake on the ground, buildings and other structures, lifelines and the local community. Comment is made on the response to the earthquake and lessons are drawn for the New Zealand situation.
Road Materials and Pavement Design, 2020
SOILS AND FOUNDATIONS, 2005
Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016), 2016
Coupled Systems Mechanics, 2012
Earthquake Engineering & Structural Dynamics, 2015
SummaryPrevious theoretical studies have shown that tank uplift, that is, separation of the tank ... more SummaryPrevious theoretical studies have shown that tank uplift, that is, separation of the tank base from the foundation, generally reduces the base shear and the base moment. However, there is a paucity of experimental investigations concerning the effect of uplift on the tank wall stresses, which is the principal parameter that controls the seismic design of liquid‐storage tanks. This paper reports a series of shake table experiments on a polyvinyl chloride model tank containing water. A comparison of the seismic behaviour of the tank with and without anchorage is described. Stochastically generated ground motions, based on a Japanese design spectrum, and three tank aspect ratios (liquid‐height/radius) are considered. Measurements were made of the stresses at the outer shell of the tank, the tank wall acceleration and the horizontal displacement at the top of the tank. While the top displacement and the tank shell acceleration increased when uplift was allowed, axial compressive ...
2022 Wireless Power Week (WPW)
Journal of the Geotechnical Engineering Division, 1981
Proceedings of the 4th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2013), 2014
Building pounding, defined as the earthquake induced collision between insufficiently spaced buil... more Building pounding, defined as the earthquake induced collision between insufficiently spaced buildings, has been recognized as a recurring urban seismic hazard. Numerous studies have been carried out in the past decades on the severity of the hazard. Most of the studies employ a contact force approach, where an elastic or viscoelastic link is placed between the colliding masses in series with a gap. The link is activated when the gap is closed and the pounding force is calculated from the deformation, and rate of change of deformation of this link. Several numerical models have been proposed to compute the pounding force. Past studies have compared the performance of these models in predicting force due to the impact of a sphere falling on a floor or a beam. However, building pounding is the collision of distributed masses i.e. slabs or beams of structures and few such experimental results exist. This study presents the force due to the pounding of two suspended reinforced concrete ...
In all major earthquakes, structures in the proximity of rivers and coastal plains, are often aff... more In all major earthquakes, structures in the proximity of rivers and coastal plains, are often affected by substantial excess pore-water pressure which may lead to soil liquefaction. The excess pore-water pressure will lead to soil softening and change in structural response. However, in the few cases where soil-structure interaction is considered during the analysis process almost always a linear model of the soil and structure is employed. While this model is simple and therefore convenient, the analyses are a poor representation of real soil behaviour. Additionally, in major urban areas most structures are closely adjacent. Therefore, the situation is more complex than free-field condition or just a stand-alone structure. The analysis of a single structure cannot capture the major characteristics of the seismic response of closely adjacent structures. In this work an elasto-plastic multi-mechanism model was used to represent soil behaviour. A coupled solid-liquid phase formulation...
Compacted fill soils in hillside areas for residential dwellings are becoming prevalent as develo... more Compacted fill soils in hillside areas for residential dwellings are becoming prevalent as development within New Zealand continues to expand. Many of these sites are located on tectonically active areas, and hence the seismic performance of such earth structures should be given due consideration. The current earth fill construction standard in New Zealand (NZS 4431:1989) provides only brief mention and no guidance regarding the seismic stability of hillside fills. Consequently, revisions to the New Zealand earth till construction standard are warranted and urgently needed. In this paper, the principal seismically-induced ground deformation mechanisms (i.e., landslides and seismic compression) in hillside fills are identified, and some existing analysis procedures are summarized. Lastly, some considerations for future New Zealand earth fill construction practices are provided.
Extensive deposits of pumice sand are found in various parts of the North Island of New Zealand, ... more Extensive deposits of pumice sand are found in various parts of the North Island of New Zealand, and their soft grained nature raises questions about their engineering properties. This paper describes an investigation of the basic properties of such a sand. The first part of the investigation involves laboratory measurements of compressibility and strength, and the second part looks at penetrometer resistance using a calibration chamber. Parallel tests on the pumice sand and a quartz sand are conducted in each case. The results are surprising. The values of the two sands are almost identical, although the pumice sand has higher compressibility. The penetrometer resistance of the pumice sand is almost independent of relative density, and only moderately influenced by confining stress. Conventional correlations between cone resistance and relative density are clearly not applicable to the pumice sand.
During past decades the destructive potential and the complexity of soil liquefaction phenomenon ... more During past decades the destructive potential and the complexity of soil liquefaction phenomenon associated with strong earthquakes has been widely documented. However, current structural seismic design generally neglects the influence of the subsoil. Design codes that deal with liquefaction usually focus the settlements that can affect the structural foundations. Additionally, most studies related to soil-structure interaction have focused on the response of an isolated structure. In reality, especially in urban areas, this assumption rarely can be justified. The omission of adjacent structures can lead to inaccurate results, especially when nonlinear behaviour of soil, e.g. resulting from liquefaction, takes place. The aim of this work was to implement a holistic approach to the study of liquefaction. The influence of an existing structure on the liquefaction potential will be presented. Also, the effects of adjacent structures on the seismic response will be investigated under co...
Earthquake Engineering & Structural Dynamics, 2021
This research addresses the influence of the load characteristics, that is, frequency content and... more This research addresses the influence of the load characteristics, that is, frequency content and maximum acceleration, on the wall stresses of an anchored water storage tank. A low‐density polyethylene tank with a range of six different aspect ratios (water height to tank radius) was tested using a shake table. Eight sine excitations that cover the lowest free vibration frequency of the tank‐water system were applied. Additionally, two sets of five Ricker wavelet excitations were utilized. Each set represents potential earthquakes with a bandwidth between a low and a high dominant frequency. The experimentally determined maximum stresses and those obtained from calculations using a common spring‐mass model employed for seismic analysis of tanks were compared. The results reveal that the relationship between the excitation frequency and the wall stresses strongly depends on the sloshing behavior, especially when the frequency of loading is in the vicinity of the lowest free–vibration frequency of the tank–water system. When the frequencies are dissimilar, there is a proportional relationship between stress and the maximum acceleration of the excitation. The spring‐mass model was found to underestimate both the maximum hoop stress (for aspect ratios greater than two) and axial stress (for aspect ratios equal to 0.5). This occurs because is the spring‐mass model cannot capture, in all cases, the contribution of chaotic sloshing to wall stress.
Geophysical Journal International, 2017
Bulletin of the New Zealand Society for Earthquake Engineering, 1994
This report describes the observations and assessments of the team members on the effects of the ... more This report describes the observations and assessments of the team members on the effects of the earthquake on the ground, buildings and other structures, lifelines and the local community. Comment is made on the response to the earthquake and lessons are drawn for the New Zealand situation.
Road Materials and Pavement Design, 2020
SOILS AND FOUNDATIONS, 2005
Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016), 2016
Coupled Systems Mechanics, 2012
Earthquake Engineering & Structural Dynamics, 2015
SummaryPrevious theoretical studies have shown that tank uplift, that is, separation of the tank ... more SummaryPrevious theoretical studies have shown that tank uplift, that is, separation of the tank base from the foundation, generally reduces the base shear and the base moment. However, there is a paucity of experimental investigations concerning the effect of uplift on the tank wall stresses, which is the principal parameter that controls the seismic design of liquid‐storage tanks. This paper reports a series of shake table experiments on a polyvinyl chloride model tank containing water. A comparison of the seismic behaviour of the tank with and without anchorage is described. Stochastically generated ground motions, based on a Japanese design spectrum, and three tank aspect ratios (liquid‐height/radius) are considered. Measurements were made of the stresses at the outer shell of the tank, the tank wall acceleration and the horizontal displacement at the top of the tank. While the top displacement and the tank shell acceleration increased when uplift was allowed, axial compressive ...