नेपाल भूकम्पको दृष्टीकोणले विश्वमा ११ औं स्थानमा पर्दछ। Indian and Eurasian plate को movement ले गर्दा नेपालमा धेरै जसो भूकम्प जाने गर्दछन्। हामी सबैलाई थाहा भएकै कुरा हो, नेपालमा २०७२ सालमा ७.८ म्याग्निच्युड को भूकम्प जाँदा धेरै धनजनको क्षती भयो तर  यसले नेपालको इन्जियरिङ्ग क्षेत्रमा भने धेरै पाठ सिकाएर गयो। वास्तवमा भन्नुपर्दा हाम्रो देशमा Earthquake Resistant Design लाई विशेष ध्यानमा राखेर संरचना बनाउन पनि त्यसपछी नै सुरु गरियो। यसको साथै प्रबलिकरण (Retrofitting) प्रविधि लाई नेपालमा प्रयोग गरी सफलता पनि प्राप्त गारियो। नेपालमा बन्ने संरचनाको भूकम्पप्रतिरोधात्मक डिजाइन का लागि बनाइएको NBC-105 कोड लाई 2020 मा पुन्रमार्जित गरी थप प्रभावकारी बनाइयो। यसरी अगाडि बढीरहदा फेरि लमजुङ भूकम्प, दार्चुला भूकम्प र भर्खरै मात्र गएको जाजरकोट भूकम्पले पनि धेरै धनजनको क्षति भयो। पछिल्लो 518 वर्ष अर्थात वि.स. 1562 सालदेखि नेपालको गोरखादेखि पश्चिममा भारतको देहरादुन सम्मको क्षेत्रमा ठूलो भूकम्प गएका छैनन्। त्यसले गर्दा सुदुरपश्चिम क्षेत्रमा ऊर्जा (Strain Energy) को ठुलो सञ्चिति भएकाले भुकम्पको अति जोखिम रहेको विभिन्न अध्ययनहरुले देखाएका छन् ।

अहिले सम्मको वैज्ञानिक अनुसन्धान अनुसार भूकम्प आउने समय र यसको केन्द्रबिन्दु (epicenter) भूकम्प आउनु पहिले नै निश्चित गर्न सकिँदैन। भूकम्पबाट सुरक्षित संरचनाहरुको निर्माण गर्नु र यसका लागि पूर्वतयारीको अवस्थामा रहनु नै यसको क्षति बाट बच्ने एक मात्र उत्तम उपाय हो । भूकम्प रोक्न नसकिने प्राकृतिक प्रक्रिया भएतापनि जोखिम न्यूनीकरण तथा पूर्वतयारीका प्रभावकारी उपायहरू अपनाएर यसबाट हुने जन–धनको क्षति धेरै हदसम्म कम गर्न सकिन्छ । नेपालको जनसंख्याको करीब एक तिहाइ जनसंख्या गाउँमा अवस्थित छ र गाउँका ८०-९० प्रतिशत घर सामान्य ढुङ्गा र माटोको जडानबाट निर्मित छन्। भूकम्पबाट जोखिम यस्ता घरहरूमा सानो रेक्टरस्केलको भूकम्पले पनि धेरै क्षति गर्दछ। साथै शहर मा भएका कतिपय घरहरु न्युनतम भूकम्पप्रतिरोधात्मक मापदण्ड अनुसार पनि बनाइएको छैन जसले गर्दा भविष्यमा आउन सक्ने भूकम्पबाट अझै धेरै धनजनको क्षति नहोला भन्न सकिन्न।

नेपालमा भूकम्प आएपछिका उदारका कार्य (Post – Disaster Recovery work) जस्तै घाइतेको उद्दार र उपचार, राहत संकलन तथा वितरण, वस्ती व्यवस्थापन लगायतका कार्यका लागि केही बजेट छुट्टाइ खर्च गरेजस्तो देखाएर सामाजिक सञ्जालमा फोटो राखेर नेताहरुले कति नै धेरै काम गरेउ भने पनि वास्तविकता भने यो भन्दा धेरै नै फरक छ। मुख्य कुरा चाहि, नेपालमा भूकम्प आउनु अगाडी नै गर्नुपर्ने गतिविधि (Pre-Disaster Work) मा त्यति जोड दिइएको देखिदैन। विपद आइपरेपछि मात्र त्यसलाई कसरी न्युनीकरण गर्न सकिन्छ भन्नु भन्दा पनि विपद नआउदै कसरी जोखिम न्युनिकरण (Risk minimization) गर्न सकिन्छ भन्ने कुरालाई गम्भीर रुपमा लिनु आवश्यक छ। कुनै पनि विपद् आउनु पुर्व र आएपश्चात हुने प्रक्रियाहरु तलको चित्रमा देखाइएको छ।

भूकम्पीय जोखिम न्यूनीकरण गर्ने उपायहरु

(क) भूकम्प प्रतिरोधी भौतिक संरचना निर्माण (Construction of Earthquake Resistant Structure)

भूकम्प आफैले कसैलाई मार्दैन तर मानिसले बनाएका कमजोर घर, भवन, पुल बाँध जस्ता भौतिक संरचनाहरू भूकम्पको बेला भत्किंदा जन धनको भारी क्षति हुने गर्दछ । विगतका भूँइचालाहरूले भत्काएका र बचेका संरचनाहरूको विस्तृत अध्ययन तथा विश्लेषणका आधारमा भूकम्प प्रतिरोधी निर्माण प्रविधिको विकास भएको छ । उक्त प्रविधिको प्रयोग गरेर बनाइएका घरहरू भूकम्पको बेला सुरक्षित रहन्छन् र जनधनको क्षति नगन्य हुन्छ । प्रचलित निर्माणको तुलनामा कुल लागतको ५-७ % बढी लगानी गरेर साविककै निर्माण सामग्रीहरूबाटै शहर बजार वा गाउँघरतिर बन्ने सबै खाले घरहरुलाई भूकम्प प्रतिरोधी बनाउन सकिन्छ ।

(ख) भूकम्पीय प्रबलीकरण (Retrofitting)

पहिल्यै बनिसकेका पुराना वा नयाँ घरहरू कमजोर छन् भने तिनलाई विशेष प्रकारको मर्मत संभार गरेर संभावित भूकम्पबाट सुरक्षित पार्ने कामलाई भूकम्पीय प्रबलीकरण भनिन्छ । भूकम्प थेग्ने नयाँ घर बनाउँदा लाग्ने खर्चको अधिकतम 30 प्रतिशत लगानी गरेर सम्भब छ भने बनिसकेका पुराना वा नयाँ कमजोर घरहरूलाइ भूकम्प प्रतिरोधी पार्न सकिन्छ । थोरै लगानीमा पुराना वा नयाँ कमजोर घरहरूमा भूकम्पबाट हुन सक्ने ठूलो जन धनको क्षति जोगाउन भूकम्पीय प्रबलीकरण उपयुक्त विकल्प हो । विशेषतः विद्यालय, स्वास्थ्य केन्द्र आदि सार्वजनिक प्रयोग हुने भवनहरु प्रवलिकरणको पहिलो प्राथमिकतामा पर्नु स्वभाविक हो ।

(ग) गैरसंरचनात्मक जोखिम अल्पीकरण (Mitigation of Non-structural risk)

हामीले घर, अफिसमा बरोबर प्रयोग गर्ने यक, दराज, शोकेस, टेलिभिजन, पंखा हिटर जस्ता फर्निचर तथा उपकरणहरु भूकम्पको बेला ढल्दा खस्दा पनि जन धनको क्षति हुने गर्छ । भवनको बलियो वा कमजोरपनामा प्रत्यक्षतः सामेल नहुने यी गैर-संरचनात्मक अंगहरु पनि बलियो हुनु आवश्यक छ । विनासकारी भूकम्पहरुमा परी चोटपटक लागेको तथा मृत्यु हुनेहरुमध्ये करिब आधा जति गैर-संरचनात्मक जोखिमका कारण हुने गर्दछ । त्यसैले हामीले आफ्नो घर, कार्यालय तथा विद्यालयमा प्रयोग गर्ने फर्निचर, उपकरणहरु लगायत सजावटका सरसमानहरु सुरक्षित तवरले बाँधेर, अड्काएर, अड्याएर नढल्ने, नखस्ने गरी राख्नुपर्छ ।

नेपालमा भविष्यमा आउन सक्ने भूकम्पबाट बच्नका लागि विपद्पुर्व गर्नुपर्ने कार्यहरु:

1. भूकम्पलाई अलग दैवी घटनाको रुपमा नलिइकन एक प्राकृतिक प्रक्रियाको रुपमा वैकल्पिक सोच राख्नुपर्ने
2. देशभित्र रहेका सार्वजानिक तथा निजी संरचनाहरुको विधमान खतरा, जोखिम (Risk) र संकटाभिमुखता (vulnerability) हरुको लेखाजोखा (Visual Assessment) गरेर विभिन्न समुह (For example: Red Zone, Yellow Zone, Green Zone) मा विभाजन गरी शहरी विकास मन्त्रालय, शहरी विकास तथा भवन निर्माण विभाग, स्थानीय पुर्वाधार विभाग, केन्द्रीय, प्रदेश तथा स्थानीय सरकारको सहकार्यमा उक्त संरचनाहरुको पुन्रस्थापना, पुन्रनिर्माण र प्रवलीकरणमा जोड दिने (सुरुमा Red Zone मा परेका संरचनालाई प्राथमिकता दिने र त्यसमा पनि विशेषगरी सार्वजानिक कार्यका लागि प्रयोग हुने संरचनालाई) ।
3. ग्रामीण क्षेत्रमा अबको दिनमा बन्ने संरचनालाई भूकम्प प्रतिरोधात्मक बनाउनको लागि शहरको जस्तै गरी गाउँपालिकाबाट पनि प्रत्येक संरचनाको निर्माणको स्वीकृती नलिइकन कार्य गर्न नदिने।
4. गैरसंरचनात्मक जोखिम न्युनीकरण गर्नको लागि  Non-structural elements (जस्तै – फर्निचर, उपकरण, सजावटका सामानहरु आदि ।)  लाई बाध्ने (दराज, Racks आदि), स्थान्तरण गर्ने (भवनको माथिल्लो तलाहरुबाट गर्ह्रौ सामान भुइतलामा लग्ने), हटाउने (पोखिन सक्ने खतराजन्य पदार्थहरु, रासायनिक पदार्थहरु), टेवा दिने (सिलिङको बतीहरुलाई थप support दिने), विस्थापन गर्ने (गर्ह्रौ छाना, Masonry Gable etc. replacement), परिवर्तन गर्ने (झ्यालको ऐनाको भित्री भागलाई छेक्नलाई प्लाष्टिक ल्यामिनेशन गर्ने), संरचनासँग सुरक्षित तवरले जोड्ने (पानी ट्याङ्की), Clips and Hooks को प्रयोग गरी बाध्ने आदि।
5. भूकम्पका कारण सम्भावित पहिरो जाने, बाढी आउने, रुख, विजुलीका खम्बा, टावर आदि ढल्न सक्ने जस्ता जोखिमयुक्त ठाउँहरुको पहिचान गरी जोखिम न्युनीकरणका कार्य अगाडी बढाउने।
6. नेपालमा रहेको वन सम्बन्धी ऐन, नियमलाई परिमार्जन गरी आफ्नो देशको स्रोत, साधनको प्रयोग गर्दै काठ (Timber) लाई मुख्य निर्माण सामग्रीको रुपमा प्रयोगमा ल्याउने, जसले गर्दा संरचनाको Self-Weight (Dead Load) घट्दछ र संरचना पनि भूकम्प प्रतिरोधात्मक हुनेगर्दछ।
7. सार्वजानिक भवनहरु जहा पब्लिकको बढी ओहोरदोहोर हुने गर्दछ, त्यहा संकटकालीन योजना (Emergency Plan) को नक्सा तयार गरी भवनको ठाउ-ठाउमा प्रष्टसँग देखिने गरी टाँस्नुपर्दछ। विशेषगरी उक्त योजनामा प्रयोग गरिने बाटोहरु (Exit way in Emergency Period) छोटो र सुरक्षित हुनुपर्ने कुरालाई प्राथमिकता दिनुपर्दछ।
8. भुकम्प आउनुपुर्व र भुकम्प आइसकेपछि गर्नै पर्ने र गर्नै नहुने कार्यहरु सम्पुर्णमा जानकारी गराउने।
9. भुकम्पीय पुर्वअभ्यास (Drill) गर्ने गराउने, “घुँडा टेकी गुँडुल्की ओत लागी समात” (Drop, cover and Hold on) गर्न सिकाउने
10. भुकम्पबाट सुरक्षित रहनको लागि केन्द्रीय स्तरमा, जिल्लास्तरमा र स्थानीय स्तरमा विभिन्न कार्यक्रमहरु आयोजना गर्नुका साथै तालिमहरु दिने । विशेष प्राथमिकताका साथ गाँउघरमा निर्माणसम्बन्धी कार्य गर्ने गराउने डकर्मी र सिकर्मीलाई निर्माण गर्ने तरिका सम्बन्धी तालिम दिने।

Author: Er. Sumit Paudel, Earthquake Engineering Student, Thapathali Campus

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Case Studies are descriptions of real situations that provide a context for engineers to explore decision making in the face of socio-technical issues. Case studies typically involve complex issues where there is no single correct answer. Most engineering case studies available pertain to engineering ethics.

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The Process of analyzing a case study encourages several learning tasks.

1.Exploring the nature of a problem and circumstances that affect a decision or solution.

2.Sensitivity to ethical issues, sometimes called “developing a moral imagination,” or the awareness of the needs of others and that there is an ethical point of view.

3.Recognition of ethical issues or the ability to see the ethical implications of specific situation and choices.

4.Learning about others’ viewpoints and how they may be taken into account.

5.Ability to analyze and critically evaluate ethical dilemmas’ including an understanding of competing values, and the ability to scrutinize options for resolution.

6.Ethical responsibility, or the ability to make a decision and take action.

7.Tolerance for ambiguity, or the recognition that there may be no single idea solution to ethically problematic situations. Predicting outcomes and consequences.

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Steps in resolving ethical dilemmas

1)Engineering Ethics

2)Consequentialist Approach – basically argues “no harm, no foul”.

3)We are going to assume that if there are any laws involved, you plan to obey them. This is not to say that it is always morally wrong to break laws.

4)List the full range of alternative courses of action available to you.

5)Assume you have a variety of options. Consider the range of both positive and negative consequences connected with each one. Who will be helped by what you do? Who will be hurt? What kind of benefits and harms are we talking about? How does all of this look over the long run as well as the short run? After looking at all of your options, which of your options produces the best combination of benefits – maximization and harm – minimization ?

6)Concentrate instead strictly on the actions. How do they measure up against moral principles like honesty, fairness, equality, respecting dignity of others, respecting peoples rights and recognizing the vulnerability of individuals weaker or less fortunate than others?

7)Take both parts of your analysis into account and make a decision. This strategy should give you at least some basic steps you can follow.

8)Think about the circumstances, which led to the dilemma with the intension of identifying and removing the conditions that allowed it to arise.

Sample Questions

** As a consulting engineer you were asked to monitor a water supply project financed by an NGO and handled by local water committee at Kaski district. The project was to be completed by the end of Baisakh, 2070; otherwise the donor would stop the payment. When you visited the site at the middle of Baisakh, you found that the project was not completed. The local committee requested you to submit the completion report so that they could finish the work after sometime and will be beneficial to 80 household of the village.

Answer the following questions:

1)In your opinion, who is /are responsible to finish the project on time?

2)As a consulting engineer, write a report to the NGO.

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** A number of cracks in structure as well as settlement appeared in a building designed by an engineer within two years of its completion. Municipality had approved the design and drawing. Later it is found that without any soil-investigation, structural design and detailing of reinforcement design report was prepared.

1)Discuss the position of the house owner.

2)The engineer’s role

3)Municipal role.

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** A fresh engineering graduate (Engineer A) with a specialization in water resources, looking for a job is approached by a Senior Engineer from the Department of Ground water Development (DoGD). The DoGD Engineer asks Engineer A to conduct a district wide study of the inter-links between groundwater and surface water at Rupandehi District, Nepal and also provides a sample of a report to be produced as the end product of the study. Engineer A finds that the sample report is based on a superficial study, with all the related data taken from western countries, and request for permission from the DoGD Engineer to visit the site and collect field-based data. The DOGD Engineer refuses, saying that the budget to complete the study is very low, asks Engineer A to prepare the report with data taken from text books or other reports and assures that Engineer A will not face any problem since the contract to conduct the study was obtained by a consulting company registered in the name of the DOGD Engineer’s spouse, and the DoGD Engineer himself is responsible to check the quality of the report.

Answer the following questions with appropriate justification.

a) Is it moral and ethical for Engineer A to accept the assignment and follow the suggestions of the DoGD Engineer?

b) Should Engineer A do his/her best and use data from other report and text books to prepare the report?

c) Should Engineer A simply refuse to accept the assignment and forget about it?

d) Should Engineer A accept the assignment, collect the relevant documents from the DOGD engineer and then report the case to CIAA?

e) Will Engineer A face any problem if he/she just follows the suggestions of the DOGD Engineer?

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** You are a structural engineer working for a consulting firm. You designed a shopping complex building as per the requirements of the client. The work has been done under your supervision. After five years the owner decided to add two more stories and come to you to prepare a design. While reviewing the previous design you found that the building will be unsafe for constructing additional floors due to poor underground soil condition. Your supervisor influences you to prepare the design otherwise you will be fired from the job. What should you do in such a situation? Prepare a case study based on engineering ethic.

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** A client came to a designer and asked to design a multistoried building. The soil type of the proposed site found not suitable for that type of structure. The designer hesitated to design the building. The client said that actually he was not going to build the building. He wanted to collect the money from outside sources showing that design as a proposal for his venture and he wanted to utilize that money in other business. Now, what should the designer do in such a situation and why? Explain with the reference to ethics and professionalism.

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** Highly dense and old city of Kathmandu, Bhaktapur and Lalitpur district were fully destroyed due to recent earthquake-2072. The road in those areas are hardly 10 feet wide but buildings were of minimum four storied. It is difficult to enter and pass any vehicle through these areas. Now supposing yourself as an Engineer appointed with full responsibility to manage the debris and reconstruct the areas, how will you handle the case to complete it within provided time frame?

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** During quality control visit in a remote village, it has been found that a building is being constructed on the bank of a river, and it will be damaged due to flood. Approximately 25% of the construction was completed. The survey was done by your friend with the consent of the local people. However, the quality of construction was as per specification. Your job is limited to control the quality of building only. Discuss the case and recommend your views on whether to continue the construction or not?

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** Both Bibek and Akhil, consultant engineers, slipped on the floor of CTC Mall during their inspection visit, which was under construction, causing serious injury. During investigation, it was revealed that the floor was not constructed as per design and specification making it slippery. The flooring work was subcontracted to Govinda on recommendation of Bibek. Who is to blame? Give reason.

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** Loksewa Office published different vacancies for the post of Engineer in Gorkhapatra dated 2074-6-15. A fresh graduate Engineer from ABC College went at Loksewa Office to apply an application for same post. He got the information from Notice Board of Loksewa that the NEC membership is must as one of the essential documents for the further processing of application. He applied for NEC membership with all required documents but he was unable to get the membership. He later found that his college was not registered in the Engineering Council. He appealed to consider his application to Loksewa but Loksewa denied to accept the application. Analyze the role of different parties at this case under the professionalism.

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** Engineer Mohit was appointed as engineer by District Development Committee (DDC) of Nuwakot. He was assigned an alignment survey for a proposed road connecting A VDC to B VDC. He went for alignment survey and completed his task. During survey, he used his professional

skill and knowledge. After alignment survey, a group of “Hooldanga” Political Party (HPP) protested at DDC stating that

1)Engineer Mohit has touched his 5 Ropanis of land through proposed road alignment to increase his value of land.

2)Engineering Mohit also included in his alignment survey a small piece of land of Mr. Ranabir because of his personal conflict with Ranabir some 10 year ago. On these ground the alignment survey shall be discarded and need a survey and also need to take action against Engineer Mohit.

Questions:

1)What Er. Mohit should have done?

2)What DDC should do?

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** Project Engineer of East-West Road construction project was invited to a dinner by the contractor of the same east-west construction project. After the dinner was over, Project Engineer was offered one-week long seminar at Thailand, the cost of participating in this seminar would be borne by the contractor.

Question:

Assume that you are the Project Engineer of the above said East-West road construction project. Do you participate in a one-week long seminar at Thailand? Discuss critically the possible issues associated with this event.

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To see the answer of all above questions, watch this video.

Thank you.

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Bridges are the structures that are constructed with the purpose of connecting two places separated by deep valleys or gorges or rivers and streams. Bridges are usually the cross drainage and hence a part of roads making them shorter and hence economical. For places, where the ground is uneven and undulated and where the number of rivers is large, bridges are the most economic and efficient way. It is a very convenient way.

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Objectives

• To select the possible bridge site and axis for the construction of bridge.
• To carry out surveying for topographical mapping, longitudinal and cross sections at both the upstream and downstream side of the river.

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Brief description of the site

The bridge site was surrounded by bushes. The ground was damp and swampy. The soil was soft. The hill slopes on both sides were very steep.

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Technical Specifications (Norms)

The following norms were followed while performing the bridge site survey in the field:

• Control point fixing as well as determining the length of the bridge axis had to be done by the method of triangulation. While forming triangles, proper care had to be taken such that the triangles were well conditioned, i.e., none of the angles of the triangle were greater than 120° or less than 30°.
• In triangulation, distance of Base Line must be measured in an accuracy of 1:2000.
• The triangulation angle had to be measured on two sets of readings by Theodolite and the difference between the mean angles of two sets of readings had to be within a minute.
• Carry out reciprocal levelling to transfer level from one bank to other bank of the river within a precision of ±25*sqrt(k) mm. Determine the RL of the other triangulation stations by fly levelling from the end point of bridge axis.
• Plot a topographic map indicating contour lines at suitable interval (contour interval = 1m).
• The scale for plotting the topographical map was given to be 1:500

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Equipment & Accessories

The equipment used in the survey during the preparation of topographic map in bridge site are as follows:

• Theodolite
• Levelling Machine
• Ranging Rods
• Measuring Tapes
• Leveling Staffs
• Pegs & Arrows
• Marker Pen
• Compass

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Methodology

The various methods performed during the bridge site survey were site selection, triangulation, leveling (fly levelling and reciprocal levelling), detailing by theodolite, cross section, and L-section. The brief descriptions of these methodologies are given below:

Site Selection

Site selection is the first and foremost step for the construction of bridge. Several governing factors are there for the site selection of the bridge. Geological condition, socio-economic and ecological aspect etc. guides the way of selection of bridge site. Therefore, the site was chosen such that it is laid on the very stable rocks at the bed of river as far as possible and not affect the ecological balance of the flora and fauna of the site area. The location of the bridge was selected in such a way that the heights of the roads joined by the proposed bridge were almost the same. This prevented a lot of cutting and filling to maintain a gentle gradient. The bridge site was chosen in such a way that the bridge axis was perpendicular to the flow direction and was also shorter in span so as to make the construction economical.

Topographic Survey

For the topographic survey of bridge site, triangulation was done. Triangulation is the process of measuring the angles of a chain or a network. The main purpose of the triangulation was to determine the length of the bridge axis. The triangulation also serves the control points for detailing. The bridge axis was set and horizontal control stations were fixed on either side. Distances between stations on the same sides of river i.e. base lines were measured with tape precisely. Then the interconnecting triangles were formed and angles were measured with the theodolite. The bridge axis length or span was calculated by solving the triangles using the sine rule. For vertical control, the level was transferred from the given arbitrary benchmark and RL was transferred to the stations on the next bank by reciprocal leveling while direct level transfer method was used or the same bank.

L-Section & Cross Section

For gaining an idea about bed slope, nature of the riverbed, and the variation in the elevations of the different points along the length of the river, L-section is carried out. Keeping the instrument at the control (traverse) stations on the river banks, the staff readings were taken at different points along the center line of the river up to a 150 meters upstream and 50 m downstream. Then the L-Section of the riverbed was plotted on a graph paper on scale for vertical and horizontal.

Cross-section of a river at a particular point is the profile of the lateral sides from the centerline of the river cut transverse to the L-Section at that point. The cross section can be used to calculate the volume and discharge of water at the particular section if the velocity at the cross section is known.

Levelling

a. Transferring R.L. from B.M. to control points:

The benchmark was on the rock. R.L. was transferred to the triangular station from the B.M. by fly leveling by taking the back sight-reading to the bench mark which should be within the given accuracy. The R.L. was transferred to the opposite bank of the river by reciprocal leveling.

b. Reciprocal Leveling:

This method is applicable when taping is obstructed but not the vision. For transferring the RL across the bridge reciprocal leveling was performed. This method eliminates the error due to focusing, collimation, earth’s curvature and refraction of atmosphere etc.

Taking the average of the two differences we get the difference in elevation between A and B.

Detailing

Theodolite was used for detailing of the entire bridge site. The reading was taken from the different station set up. The detailing was done with respect to the skeleton formed by triangulation. The vertices of triangles serve as a control point. The details were booked, up to 150m upstream and 50m downstream. The data and the calculations have been tabulated in a systematic way.

Comments and Conclusion

Economy and durability determine the way how a bridge is designed. The bridge axis should be designed such that the span length should be minimum and the location is safe. The bridge axis should not be below the highest flood level. The bridge span was found out to be …… meters. The cross-section was taken at the banks of river and at the middle of the river to get the profile of the flowing river.

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