Benito Pacheco - Academia.edu (original) (raw)

Papers by Benito Pacheco

Research paper thumbnail of An experimental study on active tendon control of cable-stayed bridges

Earthquake Engineering & Structural Dynamics, 1993

... but is not used in this study. 3. Active sag-inducedforces (S,ii(t) and Tnu(t)). These terms ... more ... but is not used in this study. 3. Active sag-inducedforces (S,ii(t) and Tnu(t)). These terms are due to the presence of sag in the cable. In the rest of the paper, the effect of these forces is neglected. ... m,(g + 2tgwgg + w?g) + P,u + S,ii = FgocosR,t (6) ...

Research paper thumbnail of Knowing the Seismic Capacity of Our Existing Buildings: An Overview of Perspectives and Procedures

The main part of the paper enumerates six procedures to estimate seismic capacity, namely: 1) exp... more The main part of the paper enumerates six procedures to estimate seismic capacity, namely: 1) expert opinion, 2) inspection, 3) screening, 4) "EKG" testing, 5) linear analysis, and 6) nonlinear analysis. Briefly discussed are example applications of these procedures in Metro Manila, Philippines. Seismic capacity curves are presented that illustrate both the attribute of strength and of ductility. The introductory

Research paper thumbnail of GIS-based Building Damage Assessment due to A Scenario Earthquake in Metro Manila, Philippines

This paper presents the procedure for GIS-based building damage assessment which is applicable to... more This paper presents the procedure for GIS-based building damage assessment which is applicable to mega cities in the Asia-Pacific region. The procedure consists of ground motion estimation using the hybrid simulation technique, building response estimation using the capacity spectrum method, and damage distribution estimation using the GIS building inventory data. The procedure is applied to Metro Manila, Philippines. The results

Research paper thumbnail of A Review of Road Pavement Engineering Practice in the Philippines

Research paper thumbnail of Disaster Risk Management Background of Dmaps for Infrastructure

Philippine Engineering Journal, Aug 26, 2010

... Some of these biases in fact correspond to well-identified statistical biases; others are yet... more ... Some of these biases in fact correspond to well-identified statistical biases; others are yet ... UNISDR (2009a) goes as far as recommending dealing more directly with so-called underlying “risk ... improved coping capacities in order to lessen the adverse impacts of hazards and the ...

Research paper thumbnail of Three-Dimensional Nonlinear Time-History Analysis of Two-Storey Concrete Wall-Type Structure

Philippine Engineering Journal, Aug 14, 2013

Research paper thumbnail of 2自由度非比例減衰系における複素固有モ-ドの近似解〔英文〕

Research paper thumbnail of ケーブル・はりモデルを用いた斜張橋の内部共振に関する実験と解析

Doboku Gakkai Ronbunshu, 1991

Research paper thumbnail of Damage Caused by Typhoon Haiyan in the Philippines, Review of Structural Regulations and Practice, and Research Developments in Wind Engineering

Wind Engineers, JAWE, 2015

Research paper thumbnail of 摂動法による非比例減衰線形多自由度系のモ-ド解析〔英文〕

Research paper thumbnail of Frequency Amd Damping of Tower-Soil System with Partial Uplift of Footing

PROCEEDINGS OF THE JSCE EARTHQUAKE ENGINEERING SYMPOSIUM, 1985

Research paper thumbnail of Nonlinear waves and dynamic pressures in rectangular tuned liquid damper (TLD). Simulation and experimental verification

Doboku Gakkai Ronbunshu, 1989

Tuned Liquid Damper (TLD) utilizing the motion of shallow liquid for absorbing and dissipating th... more Tuned Liquid Damper (TLD) utilizing the motion of shallow liquid for absorbing and dissipating the vibrational energy is studied with emphasis on liquid motion. A mathematical model based on the nonlinear shallow water wave theory is presented to describe the liquid motion in a rectangular tank. Liquid damping is evaluated semianalytically and is included in the formulation. Mechanical properties of TLD are also experimentally investigated using the shaking table. It is found that the liquid motion in TLD is strongly nonlinear and reveals a hardening-spring property even under small excitation. Good agreements between the simulation and the experimental results are shown when no breaking wave occurs. The model presented in this study is expected to serve as a tool for TLD design.

Research paper thumbnail of APEC-WW-2010 Country Report: Philippines

This paper has two main parts, talking about recent developments in structural and environmental ... more This paper has two main parts, talking about recent developments in structural and environmental wind engineering in the Philippines. The first few sections discuss the new wind loading provisions of the 6 th and latest edition of the National Structural Code of the Philippines, or the NSCP 2010, which are primarily based on those in the ASCE 7-05 provi-sions. Additional features of the NSCP 2010 that differentiate it from the ASCE7-05 provi-sions are discussed, namely: foregoing a wind zone map in favor of a wind zoning table, appli-cation of "rigid" and "flexible" structure classification to buildings only, and provision of a different set of gust effect factor formulations for "other," non-building structures as well as guidelines for estimation of natural frequencies and damping ratios. The last section dis-cusses current environmental wind engineering conditions and relevant policies.

Research paper thumbnail of Classical impact damper and pendulum impact damper for potential civil engineering application

Doboku Gakkai Ronbunshu, 1990

The classical impact damper (CID) and the pendulum impact damper (PID) are studied for the suppre... more The classical impact damper (CID) and the pendulum impact damper (PID) are studied for the suppression of horizontal vibrations of civil engineering structures. Experiments on the PID to verify the validity of the mathematical model are done and comparisons with simulation results are provided. Parametric study under harmonic excitation shows that the effectiveness of the CID is sensitive to changes in the amplitude of the excitation. On the other hand, the PID is insensitive to changes in the amplitude of the excitation when its frequency is close to the structural frequency, and it is less sensitive to deviations in tuning than the tuned mass damper (TMD). Comparison of the CID, PID and TMD shows optimum efficiency in terms of mass ratio, under steadystate motion and ideal conditions, to be highest for the TMD and lowest for the PID. Included is a discussion of the practical constraints that may govern the actual choice of damper.

Research paper thumbnail of SEISMIC RESPONSE ANALYSIS OF NONPROPORTIONAL DAMPING SYSTEM DUE TO RESPONSE SPECTRUM METHODBy Yoshikazu YAMADA and Kenji KAWANO

Doboku Gakkai Ronbunshu, 1988

A simple evaluation of peak seismic response of nonproportionally damped system is indeed a timel... more A simple evaluation of peak seismic response of nonproportionally damped system is indeed a timely topic and the writers read the authors paper with much interest. We have some questions on certain points, however, that we hope the authors may clarify. (1) When seismic response spectrum, together with the concept of modal superposition, is used in calculating the peak response of a multi-degree-of-freedom (MDOF) system, certain rules of modal combination (other than simple addition or superposition) become necessary because the respective peaks of the different modes generally do not occur at the same instant. Examples of modal combination rules are Square-Root-of-Sum-of-Squares (SRSS) (Refs. 14 and 16) and Complete Quadratic Combination (CQC) (Refs. 10 and 15). These have probabilistic background or

Research paper thumbnail of Parametric studies on tuned liquid damper (TLD) using circular containers by free-oscillation experiments

Doboku Gakkai Ronbunshu, 1988

A new kind of damper, Tuned Liquid Damper (TLD) relying on motion of shallow liquid in a rigid cy... more A new kind of damper, Tuned Liquid Damper (TLD) relying on motion of shallow liquid in a rigid cylinder, is experimentally studied. Prototype-sized circular containers with diameters 40 cm and 60 cm and partially filled with water, are attached to a single-degreeof-freedom structural model with natural period of 2 sec. The damper effect is measured in terms of the increase in the logarithmic rate of decrement of free oscillation of the main structure. The structural displacements range from 8 cm down to 0.25 cm. It is seen that, for large damping effect at small amplitude of structural vibration, it is necessary to tune the fundamental sloshing period of the liquid to the natural period of structure; hence the name Tuned Liquid Damper. Breaking of surface waves, which is dependent on structural vibration amplitude, appears to be a major mechanism of energy dissipation in the range of displacements considered. Also investigated are the effects of: ratio of liquid frequency to structure frequency; liquid viscosity; container bottom roughness; container roof height; ratio of liquid mass to structure mass; and container diameter.

Research paper thumbnail of Interaction of tuned liquid damper (TLD) and structure. Theory, experimental verification and application

Doboku Gakkai Ronbunshu, 1989

The interaction between rectangular Tuned Liquid Damper (TLD) and structure is investigated both ... more The interaction between rectangular Tuned Liquid Damper (TLD) and structure is investigated both experimentally and theoretically. A TLD-structure interaction model is developed where the dynamic interaction force is theoretically evaluated by applying the nonlinear shallow water wave theory. Good agreements are found between the experimental results and the theoretical simulation within the range where no breaking of wave occurs inside the TLD. Effectiveness of TLD is demonstrated for sinusoidal forced excitation. An example of TLD design procedure is also given using the TLD-structure interaction model.

Research paper thumbnail of Knowing the Seismic Capacity of Our Existing Buildings: An Overview of Perspectives and Procedures

The main part of the paper enumerates six procedures to estimate seismic capacity, namely: 1) exp... more The main part of the paper enumerates six procedures to estimate seismic capacity, namely: 1) expert opinion, 2) inspection, 3) screening, 4) "EKG" testing, 5) linear analysis, and 6) nonlinear analysis. Briefly discussed are example applications of these procedures in Metro Manila, Philippines. Seismic capacity curves are presented that illustrate both the attribute of strength and of ductility. The introductory part of the paper is an overview of the interest by owners, regulators, engineers, geologists, and other parties in the seismic performance of existing individual buildings, building types, and building population. Various performance levels are enumerated that consider both the non-structural and the structural components. Both seismic capacity and seismic demand (which together determine the seismic performance) are shown as combinations of force (or acceleration) and deformation (or displacement) parameters.

Research paper thumbnail of Earthquake damage estimation in Metro Manila, Philippines based on seismic performance of buildings evaluated by local experts’ judgments

Soil Dynamics and Earthquake Engineering, 2008

Building damage due to a scenario earthquake in Metro Manila, Philippines is estimated based on s... more Building damage due to a scenario earthquake in Metro Manila, Philippines is estimated based on seismic performance of the buildings evaluated by local experts' judgments. For the damage estimation, building capacity curves and fragility curve are developed from ...

Research paper thumbnail of Estimation Curve for Modal Damping in Stay Cables with Viscous Damper

Journal of Structural Engineering, 1993

To simplify the procedure of designing viscous dampers for stay cables in bridges, a universal es... more To simplify the procedure of designing viscous dampers for stay cables in bridges, a universal estimation curve is proposed that relates the modal damping ratio of the cable with attached damper, the mode number, the damper size, the damper location, and three ...

Research paper thumbnail of An experimental study on active tendon control of cable-stayed bridges

Earthquake Engineering & Structural Dynamics, 1993

... but is not used in this study. 3. Active sag-inducedforces (S,ii(t) and Tnu(t)). These terms ... more ... but is not used in this study. 3. Active sag-inducedforces (S,ii(t) and Tnu(t)). These terms are due to the presence of sag in the cable. In the rest of the paper, the effect of these forces is neglected. ... m,(g + 2tgwgg + w?g) + P,u + S,ii = FgocosR,t (6) ...

Research paper thumbnail of Knowing the Seismic Capacity of Our Existing Buildings: An Overview of Perspectives and Procedures

The main part of the paper enumerates six procedures to estimate seismic capacity, namely: 1) exp... more The main part of the paper enumerates six procedures to estimate seismic capacity, namely: 1) expert opinion, 2) inspection, 3) screening, 4) "EKG" testing, 5) linear analysis, and 6) nonlinear analysis. Briefly discussed are example applications of these procedures in Metro Manila, Philippines. Seismic capacity curves are presented that illustrate both the attribute of strength and of ductility. The introductory

Research paper thumbnail of GIS-based Building Damage Assessment due to A Scenario Earthquake in Metro Manila, Philippines

This paper presents the procedure for GIS-based building damage assessment which is applicable to... more This paper presents the procedure for GIS-based building damage assessment which is applicable to mega cities in the Asia-Pacific region. The procedure consists of ground motion estimation using the hybrid simulation technique, building response estimation using the capacity spectrum method, and damage distribution estimation using the GIS building inventory data. The procedure is applied to Metro Manila, Philippines. The results

Research paper thumbnail of A Review of Road Pavement Engineering Practice in the Philippines

Research paper thumbnail of Disaster Risk Management Background of Dmaps for Infrastructure

Philippine Engineering Journal, Aug 26, 2010

... Some of these biases in fact correspond to well-identified statistical biases; others are yet... more ... Some of these biases in fact correspond to well-identified statistical biases; others are yet ... UNISDR (2009a) goes as far as recommending dealing more directly with so-called underlying “risk ... improved coping capacities in order to lessen the adverse impacts of hazards and the ...

Research paper thumbnail of Three-Dimensional Nonlinear Time-History Analysis of Two-Storey Concrete Wall-Type Structure

Philippine Engineering Journal, Aug 14, 2013

Research paper thumbnail of 2自由度非比例減衰系における複素固有モ-ドの近似解〔英文〕

Research paper thumbnail of ケーブル・はりモデルを用いた斜張橋の内部共振に関する実験と解析

Doboku Gakkai Ronbunshu, 1991

Research paper thumbnail of Damage Caused by Typhoon Haiyan in the Philippines, Review of Structural Regulations and Practice, and Research Developments in Wind Engineering

Wind Engineers, JAWE, 2015

Research paper thumbnail of 摂動法による非比例減衰線形多自由度系のモ-ド解析〔英文〕

Research paper thumbnail of Frequency Amd Damping of Tower-Soil System with Partial Uplift of Footing

PROCEEDINGS OF THE JSCE EARTHQUAKE ENGINEERING SYMPOSIUM, 1985

Research paper thumbnail of Nonlinear waves and dynamic pressures in rectangular tuned liquid damper (TLD). Simulation and experimental verification

Doboku Gakkai Ronbunshu, 1989

Tuned Liquid Damper (TLD) utilizing the motion of shallow liquid for absorbing and dissipating th... more Tuned Liquid Damper (TLD) utilizing the motion of shallow liquid for absorbing and dissipating the vibrational energy is studied with emphasis on liquid motion. A mathematical model based on the nonlinear shallow water wave theory is presented to describe the liquid motion in a rectangular tank. Liquid damping is evaluated semianalytically and is included in the formulation. Mechanical properties of TLD are also experimentally investigated using the shaking table. It is found that the liquid motion in TLD is strongly nonlinear and reveals a hardening-spring property even under small excitation. Good agreements between the simulation and the experimental results are shown when no breaking wave occurs. The model presented in this study is expected to serve as a tool for TLD design.

Research paper thumbnail of APEC-WW-2010 Country Report: Philippines

This paper has two main parts, talking about recent developments in structural and environmental ... more This paper has two main parts, talking about recent developments in structural and environmental wind engineering in the Philippines. The first few sections discuss the new wind loading provisions of the 6 th and latest edition of the National Structural Code of the Philippines, or the NSCP 2010, which are primarily based on those in the ASCE 7-05 provi-sions. Additional features of the NSCP 2010 that differentiate it from the ASCE7-05 provi-sions are discussed, namely: foregoing a wind zone map in favor of a wind zoning table, appli-cation of "rigid" and "flexible" structure classification to buildings only, and provision of a different set of gust effect factor formulations for "other," non-building structures as well as guidelines for estimation of natural frequencies and damping ratios. The last section dis-cusses current environmental wind engineering conditions and relevant policies.

Research paper thumbnail of Classical impact damper and pendulum impact damper for potential civil engineering application

Doboku Gakkai Ronbunshu, 1990

The classical impact damper (CID) and the pendulum impact damper (PID) are studied for the suppre... more The classical impact damper (CID) and the pendulum impact damper (PID) are studied for the suppression of horizontal vibrations of civil engineering structures. Experiments on the PID to verify the validity of the mathematical model are done and comparisons with simulation results are provided. Parametric study under harmonic excitation shows that the effectiveness of the CID is sensitive to changes in the amplitude of the excitation. On the other hand, the PID is insensitive to changes in the amplitude of the excitation when its frequency is close to the structural frequency, and it is less sensitive to deviations in tuning than the tuned mass damper (TMD). Comparison of the CID, PID and TMD shows optimum efficiency in terms of mass ratio, under steadystate motion and ideal conditions, to be highest for the TMD and lowest for the PID. Included is a discussion of the practical constraints that may govern the actual choice of damper.

Research paper thumbnail of SEISMIC RESPONSE ANALYSIS OF NONPROPORTIONAL DAMPING SYSTEM DUE TO RESPONSE SPECTRUM METHODBy Yoshikazu YAMADA and Kenji KAWANO

Doboku Gakkai Ronbunshu, 1988

A simple evaluation of peak seismic response of nonproportionally damped system is indeed a timel... more A simple evaluation of peak seismic response of nonproportionally damped system is indeed a timely topic and the writers read the authors paper with much interest. We have some questions on certain points, however, that we hope the authors may clarify. (1) When seismic response spectrum, together with the concept of modal superposition, is used in calculating the peak response of a multi-degree-of-freedom (MDOF) system, certain rules of modal combination (other than simple addition or superposition) become necessary because the respective peaks of the different modes generally do not occur at the same instant. Examples of modal combination rules are Square-Root-of-Sum-of-Squares (SRSS) (Refs. 14 and 16) and Complete Quadratic Combination (CQC) (Refs. 10 and 15). These have probabilistic background or

Research paper thumbnail of Parametric studies on tuned liquid damper (TLD) using circular containers by free-oscillation experiments

Doboku Gakkai Ronbunshu, 1988

A new kind of damper, Tuned Liquid Damper (TLD) relying on motion of shallow liquid in a rigid cy... more A new kind of damper, Tuned Liquid Damper (TLD) relying on motion of shallow liquid in a rigid cylinder, is experimentally studied. Prototype-sized circular containers with diameters 40 cm and 60 cm and partially filled with water, are attached to a single-degreeof-freedom structural model with natural period of 2 sec. The damper effect is measured in terms of the increase in the logarithmic rate of decrement of free oscillation of the main structure. The structural displacements range from 8 cm down to 0.25 cm. It is seen that, for large damping effect at small amplitude of structural vibration, it is necessary to tune the fundamental sloshing period of the liquid to the natural period of structure; hence the name Tuned Liquid Damper. Breaking of surface waves, which is dependent on structural vibration amplitude, appears to be a major mechanism of energy dissipation in the range of displacements considered. Also investigated are the effects of: ratio of liquid frequency to structure frequency; liquid viscosity; container bottom roughness; container roof height; ratio of liquid mass to structure mass; and container diameter.

Research paper thumbnail of Interaction of tuned liquid damper (TLD) and structure. Theory, experimental verification and application

Doboku Gakkai Ronbunshu, 1989

The interaction between rectangular Tuned Liquid Damper (TLD) and structure is investigated both ... more The interaction between rectangular Tuned Liquid Damper (TLD) and structure is investigated both experimentally and theoretically. A TLD-structure interaction model is developed where the dynamic interaction force is theoretically evaluated by applying the nonlinear shallow water wave theory. Good agreements are found between the experimental results and the theoretical simulation within the range where no breaking of wave occurs inside the TLD. Effectiveness of TLD is demonstrated for sinusoidal forced excitation. An example of TLD design procedure is also given using the TLD-structure interaction model.

Research paper thumbnail of Knowing the Seismic Capacity of Our Existing Buildings: An Overview of Perspectives and Procedures

The main part of the paper enumerates six procedures to estimate seismic capacity, namely: 1) exp... more The main part of the paper enumerates six procedures to estimate seismic capacity, namely: 1) expert opinion, 2) inspection, 3) screening, 4) "EKG" testing, 5) linear analysis, and 6) nonlinear analysis. Briefly discussed are example applications of these procedures in Metro Manila, Philippines. Seismic capacity curves are presented that illustrate both the attribute of strength and of ductility. The introductory part of the paper is an overview of the interest by owners, regulators, engineers, geologists, and other parties in the seismic performance of existing individual buildings, building types, and building population. Various performance levels are enumerated that consider both the non-structural and the structural components. Both seismic capacity and seismic demand (which together determine the seismic performance) are shown as combinations of force (or acceleration) and deformation (or displacement) parameters.

Research paper thumbnail of Earthquake damage estimation in Metro Manila, Philippines based on seismic performance of buildings evaluated by local experts’ judgments

Soil Dynamics and Earthquake Engineering, 2008

Building damage due to a scenario earthquake in Metro Manila, Philippines is estimated based on s... more Building damage due to a scenario earthquake in Metro Manila, Philippines is estimated based on seismic performance of the buildings evaluated by local experts' judgments. For the damage estimation, building capacity curves and fragility curve are developed from ...

Research paper thumbnail of Estimation Curve for Modal Damping in Stay Cables with Viscous Damper

Journal of Structural Engineering, 1993

To simplify the procedure of designing viscous dampers for stay cables in bridges, a universal es... more To simplify the procedure of designing viscous dampers for stay cables in bridges, a universal estimation curve is proposed that relates the modal damping ratio of the cable with attached damper, the mode number, the damper size, the damper location, and three ...