Category Archives: Engineering Article

Construction Management Evolution & Development

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Introduction

Construction management has encountered a number of schools of thought. Succeeding schools of thought about management modify and extend existing ones but not supersede them as they still continue to exercise sway over ways in which organizations operate. Construction management is a discipline comprising systematic approaches to control time, cost and quality of a construction project based on recorded research and experience.

Though construction management must have been applied in the construction of Egypt pyramids centuries ago, but the discipline of management is relatively new, and origins of modern management can be traced to the beginning of last century. At present, there is no such thing as a comprehensive construction management theory but rather theories about the management.

By tracing the development of management as a discipline, four major schools of thought can be recognized; Classical approach (1900), Human relations approach (1925), Systems approach (1950) and contingency approach (1975).


1- Classical Approach to Management:

1.1 – Scientific management
Introduced by Fredrick Winslow Taylor (1856-1917)

By scientific management Taylor meant the systematic observation and measurement of work which was intended to replace the traditional approaches to work based on rule-of-thumb, intuition, precedent, guesswork and personal opinion. Taylor’s objective was to improve efficiency and his quest was to identify the “best way” of doing any job. Taylor argues that having established the best way of doing the job then management should select a ‘first-class’ man who has physical and intellectual qualities to achieve the required output and then systematically train him to use only the ‘best way’. Taylor sought to separate the role of managing the work; i.e., planning and organizing, from the actual execution of the work

1.2 – Administrative management
Introduced by Henri Fayol (1841-1925)

Fayol’s definition of management was in terms of five functions:
•To forecast and plan: “Examining the future and drawing up the plan of action”
•To organize: “building the structure, material, and human of the undertaking”
•To command: “marinating activity among personnel”
•To coordinate: “binding together, unifying and harmonizing all activity and effort”
•To control: “seeing that everything occurs in conformity with established rule and expressed command”

Fayol introduced fourteen general principles of administrative management. The fourteen principles are:
•Division of work: Specialization leads to greater productivity
•Authority: the right of management to issue commands and take responsibility for their actions.
•Discipline: employees should obey orders provided that management exercise good leadership.
•Unity of command: an employee should only have one boss.
•Unity of direction: people who work in the same kind of task must have common objectives.
•Subordination of individual interest to general interest: achieving the objectives of the firm must take precedence.
•Remuneration: the importance of pay as motivator is recognized.
•Centralization and decentralization: the degree of each must be appropriate to the organization and the quality of its personnel.
•Scalar chain: the creation of a hierarchy of command with the vertical flow of directions and responses is emphasized although properly controlled lateral communication is not ruled out.
•Order: both material order and social order are essential for efficiency.
•Equity: in running an organization a combination of kindliness and justice should be used in treating employees.
•Stability of tenure: Fayol believed that successful businesses tend to have more stable management personnel.
•Initiative: all personnel in an organization should be encouraged to use their initiative.
•Esprit de corps: management should seek to maintain the morale of its employees and foster a team spirit.

1.3 – Bureaucratic Model
Introduced by Max Weber (1864-1920)

Weber was concerned with the way in which authority was exercised within organizations. Authority, where orders are voluntarily obeyed by those receiving them, was distinguished from power, which is the ability to force people to obey. Weber describes three types of organizations based on the way in which authority is legitimized. Charismatic form of organization in which authority is based on the personal qualities of the leader, traditional organizations in which the bases of authority are precedent and usage, and rational-legal in which authority stems from holding a particular position in the organization.

2- Human Relations Approach

The founder of the Human relations approach is widely recognized to be Elton Mayo, who undertook what became known as Hawthorne investigations that took place at Western Electric Company in Chicago.
Mayo concluded the following:
•Man is basically motivated by social needs
•Satisfaction at work derives from social relationships at work rather than from the work itself.
•The work group itself exerts more influence on a worker than do incentives and controls used by management.
•A manager will be effective only to the extent that he can satisfy his subordinate social needs.
Though Mayo’s research methods were heavily criticized, the impact of the Hawthorne investigations on management thinking was considerable particularly the realization of the “Human factor” and the “Informal group”

3- Systems Approach

The key concepts of the systems approach evolved in response to a rapidly changing environment. It expanded on the previous schools of thought in two ways:
•The focus of the systems Theory is the whole organization comprising a set of interacting sub-systems
•The relationship between the organization and its environment is a central concern of the systems theory.

4- Contingency Approach

The most recent school of thought about management. It combines the other three approaches and states management actions cannot always relate either to general or unique circumstances but depend on contingency factors and circumstances. In other words, the way in which an organization organizes and manages its tasks is contingent on the circumstances in which it operates.

References:
•Newcomb, R, Langford D and fellows, R Construction Management, volume I
•Handy C, Understanding Organizations.

Cofferdam

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Cofferdam adalah jenis konstruksi kedap air yang dirancang untuk memfasilitasi proyek konstruksi di daerah yang biasanya terendam, seperti jembatan dan dermaga. cofferdam adalah dipasang di area kerja dan air dipompa keluar untuk mengekspose tempat tidur tubuh air sehingga para pekerja dapat membangun mendukung struktur, membuat perbaikan, atau melakukan jenis lain bekerja di lingkungan kering. Di beberapa daerah di dunia, cofferdam adalah lebih dikenal sebagai sebuah caisson. Bekerja di dalam cofferdam bisa menjadi berbahaya jika terpasang benar atau tidak aman bertekanan, namun kemajuan dalam rekayasa telah menyebabkan peningkatan keselamatan bagi pekerja menggunakan lingkungan kerja yang unik.

Berbagai bahan dapat digunakan untuk membangun cofferdam, yang benar-benar suatu prestasi teknik. Meskipun cofferdam adalah struktur sementara, itu andal harus menahan air kembali dari area kerja dan juga menahan tekanan yang sangat tinggi agar aman, dan pembangunan cofferdams sering digunakan sebagai proyek untuk insinyur belajar kerajinan mereka. Jenis yang paling dasar dari cofferdam menggunakan lembaran logam, yang ditumbuk ke dalam tempat tidur tubuh air untuk membuat dinding kedap air. Selanjutnya, pompa digunakan untuk menarik air keluar dari kandang sehingga akan kering. Beberapa cofferdams dibangun dari kayu atau beton, sementara yang lain menggunakan mekanisme berdinding ganda, dengan filler terbuat dari bahan agregat di antara dua dinding.

Dinding cofferdam bisa memperpanjang sampai ke permukaan air, meninggalkannya terbuka pada bagian atas, atau dapat dibangun sebagai suatu struktur tertutup. Dalam air sangat dalam, cofferdams tertutup dan tekanan digunakan untuk keselamatan pekerja, sedangkan di badan air dangkal, sebuah cofferdam terbuka dapat digunakan. Pekerja mengakses cofferdam tertutup melalui menetas dan tabung, dan perawatan diambil untuk memastikan bahwa pasokan udara konsisten dan tekanan dipertahankan pada tingkat normal.

Shipwrights dan perbaikan meter juga menggunakan bentuk cofferdam portabel, yang dapat dilampirkan ke sisi kapal untuk menetapkan perbaikan di bawah permukaan air. Di laut, ini bisa menjadi cara yang berguna untuk cepat mengatasi masalah potensi sampai kapal dibawa ke dok kering untuk perbaikan jangka panjang lebih banyak. perbaikan kecil dapat dilakukan dengan cofferdam portabel di galangan kapal untuk menghindari biaya pengangkutan kapal ke dok kering untuk pekerjaan yang harus diselesaikan.

Project Control, Schedulle Control & Value Engineering

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Pengendalian Proyek
■ Biaya kontrol
■ Arus Kas Analisa
■ Kontrol Jadwal
■ Manajemen Material

Kontrol Biaya
Tindakan korektif yang dapat dilakukan meliputi:
■ Menambahkan pekerja perdagangan tambahan atau awak
■ Menambahkan atau menghapus peralatan
■ Bekerja lembur
■ Membawa di subkontraktor tambahan

Jadwal Kontrol
■ jalur Kritis – Menurut definisi, kegiatan pada jalur kritis akan menunda seluruh proyek jika mereka tertunda
■ kemajuan fisik dapat dibandingkan dengan kemajuan keuangan untuk menentukan apakah proyek tersebut adalah:
• sesuai jadwal atau terlambat
• melebihi anggaran atau di bawah anggaran

Manajemen Material
Pastikan bahwa materi yang disampaikan secara tepat waktu ke lokasi dalam kuantitas dan kualitas yang diperlukan. Ketika bahan tiba mereka adalah:
■ Dihitung
■ Diperiksa
■ jika perlu, Diuji

Harus menentukan akuntansi urutan tanggal terbaru untuk:
■ toko menggambar
• Persiapan
• penyerahan dan
• persetujuan waktu
■ memimpin waktu yang diperlukan untuk fabrikasi
■ pengiriman
■ Terlalu banyak bahan yang tersimpan di situs tersebut dapat mengakibatkan masalah:
• alokasi ruang
• cuaca kerusakan
• pencurian

Terkait Konstruksi Desain
Sementara struktur seperti:
■ Perancah
■ Formulir
■ Sementara jembatan
■ Shoring
■ Cofferdams
■ Rigging harus dirancang oleh kontraktor

Manajemen Risiko
Risiko yang melekat dalam konstruksi
■ Industri bergerak menuju mengalokasikan risiko kepada pihak yang paling mampu mengendalikan risiko spesifik
■ Mengelola risiko berarti:
• meminimalkan risiko
• mengasuransikan terhadap risiko
• dan risiko berbagi
■ Konstruksi risiko – ketidakmampuan subkontraktor untuk melakukan
■ Risiko Ekonomi – eskalasi biaya
■ Politik / resiko publik – penolakan dari proyek diperlukan izin
■ risiko fisik – kondisi bawah permukaan
■ kontrak dan hukum risiko – risiko yang diberikan oleh kontrak dimana kontraktor tidak memiliki kendali
■ risiko Desain – desain proyek yang tidak pembangun
■ Pekerja terluka atau kille
■ Sebuah kecelakaan kerja yang melukai publi tersebut
■ Sebuah kendaraan konstruksi yang terlibat dalam kecelakaan off proyek

Risiko yang terbaik ditanggung oleh pihak dengan kemampuan untuk mengendalikan risiko terbaik
Cara terbaik untuk mengelola risiko adalah untuk menghindari mereka, tetapi industri konstruksi dicirikan oleh risiko!

Kontraktor
■ mengelola risiko dengan membeli asuransi
■ Memeriksa bahasa kontrak menangani kondisi berubah …
■ Kontraktor program keselamatan kerja
■ subkontrak juga merupakan bentuk kinerja manajemen risiko membutuhkan dan obligasi pembayaran

Value Engineering (VE) ■ Fungsi analisa atau analisis nilai
■ Tujuan utama untuk mengurangi biaya proyek, tanpa mengurangi kualitas struktur
■ VE ada karena kontraktor tahu cara yang lebih baik untuk membangun proyek, dan pemilik bersedia membayar untuk pengetahuan itu!

Langkah-langkah dalam Construction Schedulling

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Perencanaan & Penjadwalan
Perencanaan: Proses memilih metode dan urutan kerja
Penjadwalan: Proses menentukan keterkaitan timing terkait operasi.

Langkah-langkah dalam Construction Schedulling
■ Pemecahan proyek menjadi kegiatan kerja
■ hubungan logika Menentukan / keterkaitan antara kegiatan.
■ Konstruksi Diagram Jaringan.
■ Menetapkan kegiatan jangka waktu untuk bekerja.
■ BPT Perhitungan menghasilkan waktu mulai, waktu selesai dan float perhitungan kegiatan.
■ Penandaan Jalur kritis
■ Konstruksi Bar Charts / Waktu bertahap diagram.

Kegiatan
■ Unsur pekerjaan yang dilakukan selama proyek atau Sebuah jumlah pekerjaan yang dapat diidentifikasi sehingga kita tahu apa yang melibatkan dan dapat mengenali, ketika mulai dan selesai.
■ Suatu aktivitas yang biasanya memiliki durasi yang diharapkan, biaya yang diharapkan, dan kebutuhan sumber daya yang diharapkan

Network Diagram
■ Setiap tampilan skematik hubungan logis dari kegiatan proyek.
■ Selalu ditarik dari kiri ke kanan untuk mencerminkan kronologi proyek.
■ Biasanya kombinasi dari panah dan node.
Terutama dari dua jenis:
1.Arrow Diagram
2.Node Diagram / Diagram Precedence

Arrow Diagram
■ Kegiatan ditunjukkan oleh panah. Hubungan antara kegiatan yang ditunjukkan oleh node / acara.
■ Panjang anak panah tidak mematuhi skala apapun.
■ Mulai-untuk-menyelesaikan hubungan.
■ Dummies.
■ Penomoran dari node / acara.
■ Milestones

EARTHQUAKE

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A. Earthquakes – What? Where? Why?

What is an earthquake?
An earthquake occurs when rocks break and slip along a fault in the earth. Energy is released during an earthquake in several forms, including as movement along the fault, as heat, and as seismic waves that radiate out from the “source” and causes the ground to shake, sometimes hundreds of km’s away.

What causes earthquakes?
Earthquakes occur from the deformation of outer, brittle portions of “tectonic plates”, the earth’s outermost layer of crust and upper mantle. Due to the heating and cooling of the rock below these plates, the resulting convection causes the adjacently overlying plates to move, and, under great stresses, deform. The rates of plate movements range from about 2 to 12 centimeters per year. Sometimes, tremendous energy can build up within a single, or between neighboring plates. If the accumulated stress exceeds the strength of the rocks making up these brittle zones, the rocks can break suddenly, releasing the stored energy as an earthquake.

Where do earthquakes occur?
Earthquakes occur all over the world; however, most occur on active faults that define the major tectonic plates of the earth. 90% of the world’s earthquakes occur along these plate boundaries (that represent about 10% of the surface of the earth). The “Ring of Fire” circling the Pacific Ocean, and including Canada’s west coast, is one of the most active areas in the world.

Can earthquakes be predicted?
With the present state of scientific knowledge, it is not possible to predict earthquakes and certainly not possible to specify in advance their exact date, time and location. However, a great deal of research is being conducted to develop reliable prediction methods.

Does a small earthquake mean that a larger earthquake is coming?
No, except for very rare exceptions. Every year, hundreds of earthquakes occur in Canada. Only a very tiny minority of these precede a larger earthquake. Although a large earthquake may be preceded by a foreshock, the occurrence of a small earthquake is not in itself a typical sign. About 1500 small earthquakes occur every year in Canada, whereas major earthquakes have occurred only a few times in this century.

A small earthquake, however, provides an ideal opportunity to offer reminders about safety measures to take before, during and after an earthquake.

Can humans trigger earthquakes?
Yes! Minor earthquakes have been triggered by human activities such as the filling of reservoirs, and the injection of fluids into wells for oil recovery or waste disposal. Such cases have been documented in many areas, including the United States, Canada, Japan, and India.

B. Earthquake Statistics – How Big? How Often?

How big can earthquakes be?
The largest earthquake ever recorded was magnitude 9.5! This earthquake struck just off the coast of southern Chile on May 22, 1960. It ruptured a segment of fault more than 1300 km long and caused a tsunami that caused destruction around the Pacific Ocean area, including Hawaii and Japan. This earthquake occurred along a subduction fault, where ocean floor is being pushed beneath a continent. This is the same plate tectonic setting as is found off the coast of southern British Columbia, Washington, Oregon, and northern California.

How often do earthquakes occur?
Earthquakes occur every day around the world. Each day there are about 1000 very small (magnitude 1-2) earthquakes on Earth (that is about one every 87 seconds!!!). Each year, on average, the Earth experiences 800 earthquakes capable of causing damage (magnitude 5-5.9), and 18 earthquakes of magnitude 7 or larger.

C. Megathrust Earthquakes

What is a megathrust earthquake?
A megathrust earthquake is a very large earthquake that occurs in a subduction zone, a region where one of the earth’s tectonic plates is thrust under another. The Cascadia subduction zone is located off the west coast of North America. From mid Vancouver Island to northern California the Juan de Fuca Plate is subducting beneath the North American Plate. The two plates are continually moving towards one another, yet become “stuck” where they are in contact. Eventually the build-up of strain exceeds the friction between the two plates and a huge megathrust earthquake occurs.

How often do megathrust earthquakes occur?
The recurrence time varies from subduction zone to subduction zone. In the Cascadia subduction zone 13 megathrust events have been identified in the last 6000 years, an average one every 500 to 600 years. However, they have not happened regularly. Some have been as close together as 200 years and some have been as far apart as 800 years. The last one was 300 years ago.

How big can they be?
Megathrust earthquake are the world’s largest earthquakes. The last Cascadia earthquake is estimated at magnitude 9. A megathrust earthquake in Chile in 1960 was magnitude 9.5, and one in Alaska in 1964 was magnitude 9.2.

Where do megathrust earthquakes occur?
The Cascadia fault, on which megathrust earthquakes occur, is located mostly offshore, west of Vancouver Island, Washington, and Oregon, although it does extend some distance beneath the Olympic Peninsula of Washington State. The large distance between the Cascadia fault and the urban centers limits the level of shaking that the urban areas are exposed to.

How do we know that megathrust earthquakes have occurred?
The sudden submergence of the outer coast when a megathrust earthquake occurs kills vegetation which can be dated. Megathrust earthquakes also cause underwater landslides off the continental shelf into the deep ocean. The landslide deposits can be recognized in core samples taken from the ocean floor.

How do we know that we will have another one in the future?
The deformation of the crust in a predictable pattern can be detected by very careful geodetic measurements using Global Positioning Satellites, precise leveling, micro-gravity measurements and changing distance measurements using laser technology.

If the shaking of a magnitude 7 is 10 times greater than a magnitude 6 and 100 times greater than a magnitude 5, is the shaking from a magnitude 9 100 times greater than a magnitude 7
No. Earthquake shaking, in the frequencies that damage buildings, increases to a maximum between a magnitude 7 and 8 earthquake, then the shaking simply involves a bigger area. However, the duration of shaking for a megathrust earthquake is much longer. It can be several minutes. This long duration can result in damage to some types of buildings that might not be damaged at the same strength of shaking produced by a smaller earthquake.

If a magnitude 6.9 earthquake can devastate Kobe, Japan, what would a magnitude 9 megathrust earthquake do to Vancouver?
The Kobe earthquake was right beneath the city and the megathrust earthquake will be about 150 kilometers from Vancouver. The damage pattern would be very different. We can get a good example of the kinds of damage Vancouver can expect to experience if we look at what happened to Anchorage, Alaska, during the 1964 magnitude 9.2 megathrust earthquakes. Anchorage is about the same distance from the Alaska subduction fault. Small buildings generally had little or no damage, unless they were affected by land sliding. Almost all the damage involved large buildings or large structures such as bridges.

Will Vancouver Island sink when a megathrust earthquake occurs?
No. Vancouver Island is part of the North American plate. The fact that there is water between Vancouver Island and the mainland is function of the current position of sea level. However, the west coast of Vancouver Island will drop as much as a meter or two when the next megathrust earthquake occurs.

Are megathrust earthquakes our biggest earthquake hazard?
No. Inland earthquakes, which are not as big but can be much closer to our urban areas and occur much more frequently, are our biggest earthquake hazard.

Why do megathrust earthquakes cause tsunamis?
The thrusting motion of megathrust earthquake causes large vertical movement on the sea floor and this displaces a large volume of water which travels away from the undersea motion as a tsunami.

Is all of coastal BC vulnerable to tsunamis from a megathrust earthquake?
No. Just the coast exposed to the open Pacific is vulnerable to damaging tsunamis waves. The areas vulnerable to tsunamis are indicated in the red-tabbed pages of the telephone books published for the coastal communities of British Columbia.

If we have lots of little earthquakes will they relieve the stress building up for a megathrust earthquake?
No. It takes many, many small earthquakes to release the amount of energy equivalent to a large earthquake. The amount of energy released increases about 40 times every time there is an increase of one unit on the magnitude scale. Thus, if we consider a small earthquake at the felt level, about magnitude 2, there would have to be 40x40x40x40x40x40x40 of these earthquakes to release the amount of energy as one magnitude 9 event. That is about one million small earthquakes a day, every day, for 500 years. That level of earthquake activity is not observed.

D. Measuring Earthquakes

Are there other magnitude scales?
Yes. The Richter scale was developed by Charles Richter in the 1930’s for use in southern California using one type of seismograph. As seismographs were deployed around the world, and as different types of seismometers were developed, it became apparent that the Richter scale was strictly valid only over a certain distance range and for limited range of shaking frequency.

What is the difference between earthquake magnitude and intensity?
An earthquake has a single magnitude value (e.g., magnitude=6.3) that is assigned based on the amount of energy released by that earthquake. The magnitude is determined using a seismograph, recording the amplitude of the ground shaking, and correcting this measurement for the distance from the earthquake source. Intensity refers to how the earthquake is felt at various locations, and a range of values (between I and XII) will be assigned. Intensity values are generally largest close to the epicenter of the earthquake, and will generally decrease with increasing distance from the epicenter (note however, that local soil conditions may increase the level of shaking).

E. Earthquake Effects

How do earthquakes cause damage?
Most earthquake damage is caused by ground shaking. The magnitude or size of an earthquake, distance to the earthquake focus or source, type of faulting, depth, and type of material are important factors in determining the amount of ground shaking that might be produced at a particular site. Where there is an extensive history of earthquake activity, these parameters can often be estimated.

The magnitude of an earthquake, for instance, influences ground shaking in several ways. Large earthquakes usually produce ground motions with large amplitudes and long durations. Large earthquakes also produce strong shaking over much larger areas than do smaller earthquakes. In addition, the amplitude of ground motion decreases with increasing distance from the focus of an earthquake. The frequency content of the shaking also changes with distance. Close to the epicenter, both high (rapid) and low (slow)-frequency motions are present. Farther away, low-frequency motions are dominant, a natural consequence of wave attenuation in rock. The frequency of ground motion is an important factor in determining the severity of damage to structures and which structures are affected.

How can we minimize the damage caused by earthquakes?
We can best minimize the damage caused by future earthquakes by understanding what causes earthquakes, where they will occur, how often they occur, how large they can be, how earthquake waves travel through the earth, what influences the level of ground shaking at a site, and by designing structures to withstand the shaking that would be expected during an earthquake. In Canada, the Geological Survey of Canada operates a network of seismograph stations to continuously monitor earthquake activity, and provides seismic hazard maps for the national Building Code of Canada so that buildings and critical structures can be designed to withstand earthquakes.

F. Earthquake Engineering and Seismic Hazard

Can buildings be designed to withstand earthquakes?
Yes! Engineers can, and are, designing earthquake-resistant structures.

What is the safest type of structure?
The safest type of structure is a modern, well-designed, and well-constructed building. Generally, wood-frame houses perform very well during an earthquake. However, even these structures are prone to damage from soil failure, chimneys may be damaged or collapse, windows may break, interior walls may crack, and those houses not securely bolted to their foundation may fail at or near ground level.

Unreinforced masonary structures (those not seismically upgraded) are generally more vulnerable to earthquake damage. For some photos of damage caused to unreinforced masonary structures during the M=7.3 Vancouver Island earthquake of 1946.

G. Earthquakes – What To Do… Before, During, and After

What should I do during an earthquake?
Falling objects pose the greatest danger during a major earthquake. In Canada, no house has ever collapsed during an earthquake. However, many types of objects may fall and cause damage or injuries. Of prime concern, therefore, is protection from falling objects such as framed pictures, light fixtures, plaster from ceilings or the upper part of walls, or chimneys which may fall outside or through the roof into the house.
When an earthquake occurs,
1. turn away from windows and other glass. Windows may break and glass shards can fly great distances;
2. take cover under a sturdy desk, table, or door frame to prevent injury from falling debris;
– if you are outside, try to keep to open areas well clear of buildings and power lines;
– if you are driving, pull over and stop your vehicle, preferably in an open area.
After an earthquake, follow emergency radio broadcasts carefully, and restrict your telephone calls to genuine emergencies.

What should I do after a strong earthquake?
1. Stay calm.
2. Help the injured, if any.
3. Speak calmly with family members, especially children about what has just happened, in order to
relieve stress.
4. Stay tuned to the radio and follow instructions.
5. Use the telephone only in an emergency.
6. Do not enter damaged buildings
7. To prevent fire, check the chimneys or have them checked before using the furnace or fireplace.
Check all gas lines.

Will more shocks be felt after a strong earthquake?
For several hours, or even days, after a strongly felt earthquake, it is quite possible that people may feel more shocks. However:

In most cases, these shocks (called aftershocks) will be smaller; therefore, the shaking will be weaker.
Aftershocks do not mean that a stronger earthquake is coming.
Aftershocks are normal; they show that the earth’s crust is readjusting after the main earthquake.
The number of felt aftershocks is quite variable and thus cannot be predicted. There might be several per day, or only several per week. However, the number of aftershocks, and their magnitude, will normally decrease with time.

It is impossible to predict either the number or the magnitude of aftershocks that might occur. These vary greatly from one region to another, according to many factors which are not yet well-understood.

H. Earthquakes, Volcanoes, and Tsunamis

Is there a link between earthquakes and volcanoes?
Yes. There are both indirect links (the movements of tectonic plates cause both earthquakes and volcanoes) and direct links (earthquakes signify the movement of lava towards the surface and sometimes indicate the imminent eruption of a volcano.

When will an earthquake cause a tsunami?
Earthquakes can trigger a tsunami when there is significant vertical movement of the sea-floor over a large area. Earthquakes at plate boundaries beneath the ocean, especially subduction earthquakes, such as the M=9 earthquake of January 26, 1700 Located to the west of Vancouver Island are particularly effective in generating tsunamis.

The rapid vertical movement of the seafloor (either up or down) displaces a large mass of water from its equilibrium position, and generates a large wave (tsunami). Tsunami’s can have wavelengths of 100’s of km’s and travel very fast on the open ocean (e.g., 700 km/hr). As they approach the shore they slow down, begin to lose energy, and the wave height increases, in some cases to 10-20 m or more. Tsunamis can travel across the ocean, and hence a large earthquake anywhere in the Pacific may affect Canada’s west coast.

Not all underwater earthquakes cause tsunamis. Most earthquakes beneath the ocean are too small to generate a tsunami. Even some very large earthquakes, such as the M=8 earthquake located just to the west of the Queen Charlotte Islands in 1949 do not generate tsunamis. In the case of this earthquake the movement of the seafloor was a horizontal slip, and not the vertical motion required to generate a tsunami.

Tsunami’s can also be generated by submarine landslides (that may be triggered by earthquakes), or underwater volcanic eruptions. However, these waves tend to lose energy quickly and their effects, although perhaps significant, are much localized.

Value Engineering

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1. INTRODUCTION
Value engineering has achieved buzz-world status in the UK construction industry. An ever increasing number of firms are offering a value engineering service. However in many cases it appears that the terminology is being used without an understanding of the underlying and many people believe value engineering is simply a cost cutting exercise. It is important that industry understands value engineering as a wider concept than build ability and that it is not merely a method of cost cutting.

Value engineering is founded on a precise methodology and has a well established track record of success. It has, and continues to offer an important opportunity for the construction industry to improve the service it gives to its clients. The clients of late 1990’s are more knowledgeable and sophisticated than they have been in the past. They are increasingly looking to the construction industry to reduce costs and to demonstrate that value for money is being achieved. Value engineering offers the means for the construction industry to satisfy those needs of their clients. The value engineering approach differs from traditional project management in it concentrates the need to provide value for money rather than the control of time and cost.

2. THE ORIGINS OF VALUE ENGINEERING
Before describing what value engineering is it is worth considering its origins. The initial development of value engineering occurred GEC in the USA during World War II in response to a need to increase production of bomber aircraft. During the period US industry was running at full capacity and certain materials were in short supply. Against the background of scarce resources a task force was established to solve the problem. Their conclusion was “if we cant get the part we must get the function.”

This approach resulted in a method which analysed the function of a component and sought its replacement with an alternative that provided the same function. It was noted that one of the benefits of this process was that the alternatives resulted in a reduction of the overall cost. The basic philosophy of value engineering was established to eliminate components (and hence their cost) which did not
contribute to the function required.

The techniques of value analysis and value engineering were developed by GEC over the next ten to twenty years and it started to spread throughout the US manufacturing industries.

3. VALUE ENGINEERING IN CONSTRUCTION INDUSTRIES
The value analysis concept was adopted by the US department of defence (DOD) for procurement in the Navy’s Bureau of Ships in the mid 1950’s. The Army and Air force soon followed suit and introduced value engineering into their operations.

In 1963 the concept was introduced by the DOD into construction works by insisting that value engineering incentive clauses were included in all contracts. This approach amounted to encouraging contractors to establish “value programs” for suggesting ore effective design solutions and offering them a share of any saving in cost. This approach was, by its very nature, limited to the later stage of the project life cycle and the suggestions put forward by contractors tended to be limited in scope.

Whilst the use of this technique continues in the USA the trend in the UK has been to implement value engineering earlier in the process- during the design phase. It is important to note that the implementation of value engineering during early design poses different problems and requires different solutions to the value engineering of a manufactured component.

4. THE NATURE OF VALUE ENGINEERING
In view of the perceived misunderstanding of the nature of value engineering it is worthwhile reviewing some of the definitions which have been put forward;

“A problem solving system implemented by the use of a specific set of techniques, a body of knowledge, and a group of learningskills. It is an organized creative approach that has for its purpose the efficient identification of unnecessary cost i.e. cost which provides neither quality nor use nor life nor appearance nor customer feature” (Miles 1961.)

“A disciplined procedure directed towards the achievement of necessary function for minimum cost without detriment to quality, reliability, performance of delivery” (Crum 1971).

“A proven management technique using a systemized approach to seek out the best functional balance between the cost, reliability and performance of a project or product …..by identifying and removing unnecessary cost” (Zimmerman and Hart 1982).

“A creative organized approach whose objective is to optimize cost and/or performance of a facility or system …… elimination or modification of anything that adds cost to an item without contributing to its required functions (Dell’ Isola 1982).

Whilst the terms used differ the emphasis is consistent and the definitions capture the flavour of value engineering from the US perspective. The consistent elements are system, creativity, function and unnecessary cost.

In global terms therefore the following definition may be used. “A systematic approach to achieving the required functions at the lowest whole life cost without detriment to performance, quality or reliability.”
The emphasis adopts a fundamentally different approach in that it concentrates on function. Value engineering does not focus on what the elements or components are but on what they do. This approach considers cost in relation to the function and recognizes the relationship of value to cost and function.
The relationship can be expressed as

VALUE = FUNCTION / COST

From the formula it can be seen that a reduction in cost which reduces also function will lead to no change in value. If function is reduced by a greater proportion than cost then value is actually a reduced. To mprove value therefore cost must be reduced while function is maintained. To be effective value engineering must concentrate on the identification and understanding of the function of a component. This
is followed by consideration of alternative ways of performing those functions.

This attention to the concept of function is what sets value engineering aside from traditional practices. The basis premise underlying the technique is that there is always a certain amount of unnecessary cost in the design of every building.

Value engineering should not, however be seen as an attack on the quality of design or on the aesthetic elements within a design. It recognizes that an aesthetically pleasing or unusual design can be of value to the client-those elements performing an essential function of “attracting customers”. A value engineering study would seek to understand the importance of such functions and seek to provide them at reduced cost.

5. TIMING OF VALUE ENGINEERING
There is widespread general agreement regarding the basic methodology of value engineering. However there remains a fairly wide diversity of opinion regarding how and when it should be applied. The use of value engineering incentive clauses in construction contracts has never been as common here in the UK as it is in the USA. There is however recognition in the UK that the greatest benefits of value engineering are to be gained from its application during early design. The underlying premise being that the decisions which have the most impact on cost, and hence the values are made during the initial stages of the design process.

In practice there is a paradox in that earlier in the design process it is intended to apply value engineering the smaller the amount of information is available. There is inevitably a trade-off between the cost reduction potential and the cost of implementing changes. This has led to a general consensus in the UK that value engineering is best conducted at the end of sketch design stage (RIBA Stage D). Other practitioners advocate the application of value engineering earlier and claim that the greatest savings can be
achieved at the concept design stage or even during briefing. From the above it is evident that the scope of a value engineering study will be determined by the timing of the exercise. A study conducted during the construction phase will be limited and restricted in this scope whereas a study during the briefing stage can, and will, be more wide ranging. Studies conducted during the briefing stage will often be likely to consider.

(source : the contruction library)

Before You Build Your New House – Steps to Home Construction:

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Building a new home begins long before the foundation is poured. Listed
here are the five most important steps you must take to avoid costly
mistakes during the construction process. For each step, follow the links
for help and resources. And, as you move from dream house to real house,
be sure to ask questions and share your progress on our architecture forum.

Plan Your Budget
Begin now to think about how much you can afford to spend and how much
building your new home is likely to cost. Chances are you will need a
construction loan and a mortgage. It’s not too early to find out what size
loan you qualify for. Also, knowing the approximate costs will help you
modify your building plans to meet your budget.
• How much will it cost?
• Building Cost Estimators

Choose Your Lot
Whether you are building your home in a suburban development or a site
with sweeping ocean views, you will almost always need to choose the land
before you select floor plans or other details. You (and any pros you
hire) will need to investigate factors such as soil condition, drainage,
zoning and building codes in the region.
• Where to build?

Line Up Your Team
Unless you are a homesteader, you will need a team of experts to design
and construct your house. Key players will include a builder, an
excavator, a surveyor and a home designer or an architect. Many homeowners
begin by selecting the builder or contractor. That pro then selects other
members of the team. However, you may also opt to hire an architect or
designer first.
• Find a Pro

Pick A Plan
Many new homes are built using stock plans from a catalog. The builder or
a home designer may make minor modifications in room size, window style or
other details. A custom-designed home, on the other hand, is created
specifically for the family which will live there. In most cases,
custom-designed homes require the services of a licensed architect.
Whether you opt for a stock or a custom design, you will be wise to choose
a plan that will meet your needs for many years to come.
• Find Plans for your Dream Home
• Building Plan Books and Catalogs

Negotiate A Contract
Be sure to get a written contract which has been signed and dated by both
the builder or contractor and the architect or designer. A contract for
new home construction will describe the project in detail and include a
listing of all the parts to be included in the house. Remember to amend
the contract if you or your team make any changes to the project later on.