Engineering title to be able to understand the application if monitoring. major class in civil engineering Homework for Structure Monitoring and Analysis Lecture-3 1 General speaking, monitoring items are divided into two groups. One is environmental items. The other is structural effects. Please list the main parameters respectively. 2 Please list the main temperature control thresholds for mass concrete casting. 3 Write down the formula for vibrating wire sensor monitoring, and then explain each parameter. 4 What is the main difficult in soil pressure cell embedding? Give your solution. 5 What is the main difficult in steel rebar gauge installation? Give your solution. 6 For a typical metro station excavation, the soil retaining structure consists of soldier beams working with crosslot bracings. However, the Classical Elastic Method and the Increment Method give different results of moment distribution in soldier beam, which is shown in the figure. How to solve the problem? Please design a monitoring system: choose the sensor type, mark the sensor locations in the figure, and then give your analysis methodology in simple word.

1. Homework for Structure Monitoring and Analysis
Lecture-3
1 General speaking, monitoring items are divided into two groups. One is
environmental items. The other is structural effects. Please list the main parameters
respectively.
1. Monitoring Items - Environmental and Structural Effects:
Environmental Items:
 Temperature
 Humidity
 Rainfall
 Wind Speed and Direction
 Soil Moisture
 Groundwater Level
Structural Effects:
 Strain
 Displacement
 Vibrations
 Acceleration
 Stress
 Load
 Crack Width
2 Please list the main temperature control thresholds for mass concrete casting.
 Initial Placement: Typically, limit temperature rise to around 70-75°F (20-
24°C) above ambient temperature.
 Maximum Temperature: Limit concrete temperature to around 160°F (71°C)
to prevent excessive heat generation.
𝐹 = 𝑓 × 10
𝑝 = 𝐾(𝐹 − 𝑓 ) + 𝐵
p- soil pressure KPA
K- Constant for equipment MPa
𝐹 - Monitored frequency modulus F
𝐹 -initial frequency modulus
B- conestant for equipment kPa

2. 4 What is the main difficult in soil pressure cell embedding? Give your solution.
Difficulty: Ensuring proper embedding without disturbing the surrounding soil, leading
to inaccurate readings.
Solution:
 Careful Installation: Use specialized tools and procedures to embed the soil
pressure cell gently without disturbing the surrounding soil. First we can dig a
hole in the soil and install the device and compact the soil again layer by layers
to restore the initial condition of the soil
5 What is the main difficult in steel rebar gauge installation? Give your solution.
Main Difficulty:
1. Heat Sensitivity of Gauges: Rebar gauges are often sensitive to heat,
and the welding process required for their installation can potentially
damage or alter the gauge properties.
2. Difficulty: Maintaining gauge alignment and avoiding damage during
installation.
Solution:
1. Preparation and Planning:
 Pre-Welding Cooling: Before welding, ensure the rebar gauge is
adequately cooled to mitigate the risk of heat damage. Submerge the
gauge in a cooling medium or use a specialized cooling device to
maintain a lower temperature.
2. Welding Techniques:
 Precise Welding: Employ skilled welders trained in precision welding
techniques to minimize heat transfer and limit the duration of welding
near the gauge area.
3. Welding Parameters:
 Controlled Heat Input: Use welding machines with adjustable settings
to precisely control heat input during welding. Lower heat settings or
intermittent welding can prevent excessive heat build-up.
4. Protective Measures:
 Heat Shielding: Use heat shielding materials or blankets around the
gauge area during welding to deflect heat away from the sensitive
components.
5. Precision Installation Tools: Use specialized tools designed for rebar gauge
installation to ensure accurate placement without damaging the gauge.

3. 6. Careful Handling: Handle the gauges with care during installation to prevent
damage to the sensitive components.
7. Quality Control: Regularly check alignment and condition during installation
to make adjustments as needed.
8. Precision Installation Tools: Use specialized tools designed for rebar gauge
installation to ensure accurate placement without damaging the gauge.
9. Careful Handling: Handle the gauges with care during installation to prevent
damage to the sensitive components.
10. Quality Control: Regularly check alignment and condition during installation
to make adjustments as needed.
Consideration:
It's crucial to balance the welding process's speed with the need for accuracy and gauge
protection. Rapid cooling should not compromise the structural integrity or accuracy
of the gauge.
Employ skilled welders experienced in welding gauges to rebar to ensure proper
execution of the welding process without compromising the gauge's functionality.
By implementing a controlled cooling method during welding, you can help minimize
heat-related damage to the steel rebar gauge, preserving its accuracy and ensuring
reliable measurements in structural monitoring applications.
6-For a typical metro station excavation, the soil retaining structure consists of
soldier beams working with crosslot bracings. However, the Classical Elastic
Method and the Increment Method give different results of moment distribution
in soldier beam, which is shown in the figure. How to solve the problem? Please
design a monitoring system: choose type of sensor, mark the locations of sensor in
the figure, and then give your analysis methodology in simply word.
When faced with discrepancies in moment distribution between different analysis
methods for a soil retaining structure involving soldier beams and crosslot bracings in
a metro station excavation, implementing a monitoring system can help verify and
improve the understanding of structural behavior. Here's a proposed approach:
Monitoring System Design:
Type of Sensor:
Strain Gauges: These sensors are suitable for measuring strain, which can help assess

4. stress distribution in the soldier beams and bracings.
Sensor Locations:
Place strain gauges at strategic positions along the soldier beams and crosslot bracings.
Install multiple gauges on each element to capture variations in strain distribution.
Analysis Methodology:
Installation:
Install strain gauges on the soldier beams and crosslot bracings as per the suggested
locations.
Ensure precise placement and calibration of the sensors.
Data Collection:
Continuously collect strain data from the sensors during excavation and construction
activities.
Collect data under various loading conditions or stages of excavation.
Comparative Analysis:
Utilize both Classical Elastic Method and Increment Method for structural analysis.
Compare the calculated moment distributions from both methods with the actual strain
data obtained from the strain gauges.
Validation and Adjustment:
Analyze the discrepancies between the calculated moments and the measured strains.
Adjust the analysis method that aligns more closely with the actual measured strains.
Refine the structural analysis by iteratively updating the chosen method based on the
monitored data.
Continuous Monitoring:
Continue monitoring the strain data as excavation progresses.
Use the real-time information to assess any changes in structural behavior or stress
distribution.
Safety Measures:
Implement safety protocols or interventions if significant discrepancies or unexpected
strain variations are detected.
Conclusion:
The proposed methodology involves integrating strain gauges on the soldier beams and

5. crosslot bracings, collecting strain data, comparing this data with the results obtained
from different analysis methods, and then adjusting the structural analysis approach
based on the monitored information. This continuous monitoring and validation process
ensure better accuracy in predicting structural behavior and helps in making informed
decisions to maintain the safety and stability of the excavation structure