Seismic Analyzing Bridges Including Soil-Abutment Interaction Report

This report presents a competency demonstration focusing on the seismic analysis of bridges, specifically addressing the critical role of soil-abutment interaction. The project involved investigating the effects of soil-abutment interaction on bridge structures during seismic events, with a focus on modeling abutment stiffness using a design-driven methodology. The report details the objectives, including identifying factors affecting bridge construction and ensuring project quality, and the author's role in supervising the project, performing mathematical calculations, and managing communication with stakeholders. Key activities included applying iterative analysis procedures to determine load displacement values, analyzing the effects of monolithic abutments under different soil conditions, and addressing issues related to earthquake damage. The report highlights the collaborative work involved, the application of theoretical knowledge, and the development of procedures for analyzing non-linear soil-abutment interaction, contributing to improved bridge design and seismic resilience.

COMPETENCY
DEMONSTRATION
REPORT
Career Episode 3
TANNAZ MAABI

CE 3.1 Project Information
Name of the project: Seismic Analyzing Bridges Including Soil-Abutment Interaction
Location of the project: [PLEASE FILL]
Project Duration: [PLEASE FILL]
Organization: [PLEASE FILL]
Role and Designation during the time: Team Member
CE 3.2 Project Background
CE 3.2.1 Characteristics of the project
I had investigated on the seismic analysis and design of the internal bridges in manner to
identify the effects of soil-abutment on it. It is an obvious factor that the interaction of the soil
structure has a crucial role in the bridge structures’ seismic response. I had supervised the project
and designed it considering the backfill soil participation at the abutments. I had executed a
design driven methodology for modelling the abutment stiffness for any of the non-linear or
linear analysis. This was executed considering the pier foundation, and backfill statistics of the
project. I had supervised the of a three-span bridge considering backfill stiffness reduction,
moments and force calculation. This project can be helpful in executing the bridge construction
and providing better approach towards the successful accomplishment of the project.

CE 3.2.2 Objectives developed for the project
I considered the importance of the execution of the project needs a proper layout and path
fort the execution of the activities involved in the project. I applied following objectives for the
whole team to accomplish the project constraints in effective manner:
 To identify the aspects affecting the bridge construction
 To supervise the project for managing the quality of the project
 To provide possible and beneficial directions on how to execute the project
 To execute the project without lacking in any factors
 To keep the budget less even delivering a high quality project
CE 3.2.3 My area of work
I had to monitor and supervise the project development of the bridge construction. I
modelled the backfill soil stiffness through using the formula Ks = Es / [(1-V2). I], where Ks is the
“soil stiffness per unit deflection per unit wall width”, Es is the backfill soil’s Young’s modulus,
v is the backfill soil’s poisson’s ratio, and I is the shape factor. I executed the mathematical
calculation for the identification of the vertical displacement of having the dimension of (a x b;
where ‘b’ is shorter than ‘a’) through the following formula:
δz = {(1 – v2) / Es}. pbI where p is describing the load per unit area of the rectangle.
I had been assigned in the phase of executing iterative analysis procedure that includes
three steps and further four sub-steps for the overall result as described in the following figure:

Figure 1: Procedures involved in Schematic presentation of Iterative Analysis
I continuously and repeatedly executed the above steps for the collection of following
data as depicted in the figure:

Figure 2: Load Displacement Diagram (Longitudinal Direction)
Figure 3: Load displacement diagram (Transverse Direction)

CE 3.2.4 Project Group
CE 3.2.5 My responsibilities throughout the project
I was responsible for looking after the growth of the ongoing activities within the project.
I had to do all the mathematical calculations and ensure that the project is moving in the right
direction and it needs to be perfect for the successfully delivery of the project. I had executed the
procedures that can be helpful in leading to greater moments and forces at the large
displacements and within the bents, attributing the fact that the soil capacity was exceeding and
backfill stiffness. I had to present exact mathematical calculation for the effective and efficient
execution of the bridge construction at the location. I done proper communication with the
supplier, the project manager and other executive stakeholders in an effective way and was
backed up efficiently due to their efforts.

CE 3.3 Distinctive Activity
CE 3.3.1 Comprehending the theory of the project
I had concern over the performance of the bridges over the highways during the
unwanted situations such as earthquake. I identified that for most of the bridges at the highway,
abutments have been a major factor for attracting a “large portion of the seismic force”, and
affects mostly in the longitudinal direction. I executed soil – abutment interaction within the
seismic loads those have been a non-linear phenomenon. This phenomenon has a very crucial
role in the response of the overall structure of the bridge.
CE 3.3.2 Engineering knowledge and skills applied in the project
Following is the result of the data collected at the project site:
Longitudinal
Earthquake
Bent #3#
My (kNm)
Bent #2#
My (kNm)
Abutment #1# displacement δ x(cm)
Proposed analyses -2528 -2825 1.640
Analysis without SSI -2003 -2138 1.323
+26% +32% +24%
Transverse Earthquake Bent #3#
Mx (kNm)
Bent #2#
Mx (kNm)
Abutment #1# displacement δ y(cm)
Proposed analyses 5062 4976 3.030
Analysis without SSI 3223 3148 1.753
+57% +58% +73%
Table 1: (Lose Soil) Monolithic Abutments

Transverse Earthquake Bent #3#
M x (kNm)
Bent #2#
M x (kNm)
Abutment #1# displacement δ y(cm)
Proposed analyses 2957 2876 1.430
Analysis without SSI 2181 2101 0.928
+36% +37% +54%
Table 2: (Medium Soil) Monolithic Abutment
Transverse Earthquake Bent #3#
M x (kNm)
Bent #2#
M x (kNm)
Abutment #1# displacement δ
y(cm)
Proposed analyses 2346 2263 0.920
Analysis without SSI 1735 1651 0.588
+35% +37% +56%
Table 3: (Dense Soil) Monolithic Abutments
CE 3.3.3 Accomplishment and task performed
He project had many vital milestones that needed to be accomplished in an effective and
efficient manner and I was assigned as a supervisor for this bridge construction project. I
modelled the backfill soil stiffness through the application of the equation mentioned earlier
considering the passive resistance of the soil. The other teammates involved in the project had
modelled the ‘Pile stiffness’ through conservative and appropriate recommendations. I tried to
manage the quality of the project at every phase of my testing and evaluation. I had presented the

daily report of the quality of the material and continuous growth to the project manager and kept
the records of every individual and the related activities.
CE 3.3.4 Identified issues and their solutions
3.3.4.1 Issues
Earthquake causing damage the bridges was one of the major concern for the long run of
the infrastructure and it needed to be eliminated from the process for enhancing the effectiveness
and efficiency of the project. Exact theoretical calculations were needed to be done precisely as
minor error can affect the whole design and delivery of the project.
3.3.4.2 Solutions
I applied the iterative analysis procedure for the determination of the values of load
displacement value in the transverse and longitudinal direction. I calculated the values in the
aspects of the monolithic abutments for all the three types of soils including loose, medium, and
dense soils. I used the formulas for the precise and accurate calculation of the values of
monolithic abutment, abutment stiffness, load displacement diagram and many as explained
earlier.
CE 3.3.6 Collaborative work
I was assigned to supervise the whole project that was being driven by hundreds of other
employees who had contributed their sector of works in effective way. I had done proper
paperwork for enlisting all the activities and accordingly schedule for the records of the current
development and future estimation of the project. I provide suitable guidance of the
modifications and manipulations those were needed to be implemented in the middle of the

project execution. I tried to manage the responsibilities and roles of every individual within the
project and supervised the project constraints in an effective and efficient manner.
CE 3.4 Project Review
CE 3.4.1 Project Overview
I had developed two procedures that can be helpful in considering “the non-linear soil-
abutment interaction under seismic loads.” The above presented procedures have been relatively
easy and simple to be applied within the bridge design. I supervised a large population of the
staffs and managed all the experimental activities for the development of an effective bridge
construction design. I had applied my theoretical knowledge in this project for determining the
exact values of the variables and aspects related to the bridge designing. I incorporated abutment
stiffness within the proposed bridge design that would be a valuable aspects in y future projects
and bridge construction sites. I had analysed the different aspects of the bridge design as
explained in the above sections and supervised the whole project under my surveillance. I
managed the communication with the suppliers and other executives for the effective information
exchange and clear every aspects related to the project delivery.
CE 3.4.2 My contribution to work
I contributed my theoretical learnings gathered during academics and applied them in an
effective manner for the deliver the project successfully. I estimated the displacements, distance
factors through applying mathematical calculations, and presented the precise and effective
values for the bents and angles of the bridge. I supervised the project in an effective way
considering that the every objective and goal of the project has been accomplished and output is