Name: plotting a horizontal curve from field data
Uploaded: 2025-03-26T15:37:10.000Z
Duration: 1 min 9 s
Channel: JoVE

ضع في اعتبارك أن المهندس المدني يجب أن يرسم منحنى أفقيا بسيطا بنصف قطر 200 متر وزاوية تقاطع 20 درجة في هذا المجال. يستخدم المهندس طريقة الإزاحات العمودية من الوتر الطويل لرسم المنحنى.  أولا ، يتم حساب طول الوتر الطويل على أنه 69.46 مترا ، ويتم ضبط الفواصل الزمنية للإزاحات العمودية على 3 أمتار. بعد ذلك ، يتم استخدام تعبير الإزاحة عند نقطة المنتصف لتحديد إحداثيات مركز الوتر الطويل ، ولضمان الدقة ، يتم التحقق من هذه القيمة مقابل الإحداثي الأوسط للمنحنى. يحدد المهندس الوتر الطويل للمنحنى على الأرض ، ويتم تمييز النقاط على فترات 3 أمتار على جانبي نقطة المنتصف. بعد ذلك ، يتم استخدام تعبير مسافة الإزاحة لحساب الإزاحات العمودية ، والتي يتم تمييزها على طول الوتر الطويل عند النقاط المقابلة. أخيرا ، يقوم المهندس بتوصيل الأطراف العلوية للإزاحات العمودية لتشكيل المنحنى.

مثال على التصميم: تعيين منحنى باستخدام بيانات التصميم

يتطلب تصميم منحنى ورسمه باستخدام البيانات الميدانية حسابات دقيقة وتنفيذا. يتم إنشاء منحنى أفقي نصف قطره 200 متر وزاوية تقاطع 20 درجة باستخدام طريقة الإزاحات العمودية من الوتر الطويل. يتم حساب الوتر الطويل ، الذي يمتد بين نقاط نهاية المنحنى ، على أنه يبلغ طوله 69.46 مترا. للحفاظ على الدقة في التخطيط ، يتم تحديد فترات 3 أمتار على طول الوتر. يحدد المهندس مسافات الإزاحة لكل فاصل زمني باستخدام صيغة الإزاحة. عند نقطة منتصف الوتر ، يتم حساب قيمة الإحداثيات والتحقق من صحتها مقابل الصيغة الإحداثية الوسطى للمنحنى ، مما يضمن التزام تصميم المنحنى بالمعايير الهندسية الدقيقة. ثم يتم تمييز الوتر الطويل على الأرض ، مع تحديد النقاط على فترات 3 أمتار على طوله على جانبي نقطة المنتصف. لكل نقطة ، يتم قياس مسافة الإزاحة العمودية وتمييزها على الأرض بزاوية قائمة على الوتر. تمثل الأطراف العليا لنقاط الإزاحة هذه موضع المنحنى على فترات زمنية محددة. من خلال توصيل الأطراف العلوية للإزاحات بسلاسة ، يتم إنشاء المنحنى على الأرض ، مع الالتزام بمواصفات التصميم. تضمن هذه الطريقة رسم المنحنى بدقة ، مما يوفر إطارا موثوقا به للمشروع.

Designing and plotting a curve using field data requires precise calculations and execution. A horizontal curve with a radius of 200 meters and an ...

design-example-setting-a-curve-using-design-data

Education

JoVE Core

Civil Engineering

الهندسة المدنية

Unit 1

الوحدة الأولى

Horizontal and Vertical Curves

المنحنيات الأفقية والرأسية

KEY TERMS AND CONCEPTS

المصطلحات والمفاهيم الرئيسية

Design Example: Setting a Curve Using Design Data

plotting a horizontal curve from field data

Plotting a horizontal curve from field data starts with careful geometric design. The curve in this example has a radius of 200 meters and an intersection angle of 20 degrees. Engineers use the method of perpendicular offsets from the long chord to place the curve on the ground.

The long chord is the straight line between the two ends of the curve. Here, its length is calculated as 69.46 meters. To improve accuracy, 3-meter intervals are marked along the chord. Offset distances at each point are then found with the offset formula.

At the midpoint of the chord, the ordinate value is calculated and checked against the middle ordinate formula for the curve. This step helps confirm that the layout matches the design geometry. The long chord is then marked on the ground, and points are set at 3-meter intervals on both sides of the midpoint.

For each marked point, a perpendicular offset is measured at a right angle to the chord. The upper ends of these offsets show the curve position at each interval. When these points are joined smoothly, the curve is laid out on the ground according to the design specifications.

Plotting a Horizontal Curve from Field Data

plotting-a-horizontal-curve-from-field-data

introduction to horizontal curves

Horizontal Curve Parts and Road Alignment

Horizontal curves connect straight road or railroad segments and help vehicles move safely through a change in direction. They are used in highway and railroad design to create smooth transitions between tangents, which are the straight path sections before and after the curve. By reducing abrupt changes, these curves can support steadier travel speed and help lower the chance of accidents. A simple horizontal curve is defined by its geometry around the intersection point, or P.I., where two...

degree of curvature and radius of curvature

degree-of-curvature-and-radius-of-curvature

Curvature Measures in Civil Engineering Curves

Degree of curvature and radius of curvature help describe how sharply a curve bends in civil engineering. The degree of curvature measures the steepness of the bend. The radius of curvature shows how tight or smooth the curve is. The degree of curvature can be found by the chord basis or the arc basis. In the chord basis method, the degree is the central angle subtended by a chord of 30.48 meters. In the arc basis method, it is the central angle subtended by an arc of length 30.48 meters. <br...

curve equations

Curve Measurements and Arc Length

Curve measurements describe the key parts of a curved line. The main values are tangent distance, chord length, middle ordinate, and total arc length. These measurements help explain a curve’s shape and size using its radius and central angle. Tangent distance, or T, is the straight-line distance from the point where two tangents meet to the start or end of the curve. It depends on the curve radius, R, and the central angle, I. These two values work together to set the curve’s layout. Chord...

horizontal curve: problem solving

Setting Out a Horizontal Curve

A horizontal curve is set out by using its radius, intersection angle, and stationing of key points. In this example, the radius is 400 meters, the intersection angle is 30 degrees, and the station of the point of curvature, or P.C., is 0 + 150 meters. The goal is to find the station values for the point of intersection, or P.I., the point of tangency, or P.T., and the midpoint of the curve. The length of the long chord is also needed. The first step is to calculate the tangent distance, T,...

field procedure for staking out curves

Surveying Curve Layout with Deflection Angles

Surveying curve layout with deflection angles turns a designed curve into stakes placed in the field. In construction, this step helps keep structures aligned along a curved path. Surveyors use calculated positions so the physical markers match the plan. The process starts by finding the curve’s geometric values. These include the radius, central angle, and tangent distances. Surveyors also identify the Point of Curvature (PC), the Point of Tangency (PT), and the midpoint of the curve. These...

introduction to vertical curves

Designing Smooth Road Grade Transitions

Vertical curves are parabolic transitions that connect different grades on highways and railroads. They help create a smooth alignment between the back tangent and the forward tangent. The back tangent is the first grade, and the forward tangent is the next grade. These curves may be symmetrical or nonsymmetrical. In a symmetrical vertical curve, the tangent lengths are equal. In a nonsymmetrical curve, the tangent lengths are different. The main points used to describe the curve are the Point...

vertical curve: problem solving

Calculating Elevations on a Vertical Curve

Vertical curves connect two roadway grades and help make the road safer, smoother, and more functional. To find the elevation at specific stations on the curve, engineers follow a set of steps based on the curve length, the grades, the Point of Vertical Intersection, or P.V.I., and the P.V.I. elevation. The first step is to locate the Point of Vertical Curvature, or P.V.C., and the Point of Vertical Tangency, or P.V.T. The P.V.C. marks the start of the curve, and the P.V.T. marks the end.

elevation of intermediate points on vertical curves

elevation-of-intermediate-points-on-vertical-curves

Finding High and Low Points on Vertical Curves

Vertical curves help roadways move smoothly from one grade to another. Engineers use them to connect changing slopes and keep the road profile safe and even. To design these curves, they calculate intermediate elevations and find the highest or lowest point on the curve. Intermediate elevations on a vertical curve are found with the tangent offset method. This method uses the starting elevation, the grades at each end, and the curve shape. It gives the elevation of any point along the curve by...

sight distance in a vertical curve

Road Safety on Crest and Sag Curves

Road safety on crest and sag curves depends on how far drivers can see ahead. In roadway design, vertical curves must give drivers enough sight distance to notice hazards and react in time. This affects safety, driver comfort, and how efficiently the transportation network works. Vertical curves are grouped into two main types: crest curves and sag curves. A crest curve is shaped like a hilltop, so the road can block the view of what is beyond it. For these curves, sight distance is based on...

design example: setting a curve using design data

Plotting a horizontal curve from field data starts with careful geometric design. The curve in this example has a radius of 200 meters and an intersection angle of 20 degrees. Engineers use the method of perpendicular offsets from the long chord to place the curve on the ground. The long chord is the straight line between the two ends of the curve. Here, its length is calculated as 69.46 meters. To improve accuracy, 3-meter intervals are marked along the chord. Offset distances at each point...

key terms and concepts

See how a 200 m horizontal curve is laid out from field data using a long chord, 3 m intervals, and perpendicular offsets for accurate ground marking.

Plotting a Horizontal Curve from Field Data | JoVE K12

JoVE Core Civil Engineering provides a foundational exploration of essential construction materials in civil engineering, focusing on bricks, stones, steel, wood, and concrete through easy-to-understand animated videos. This collection covers the properties, manufacturing processes, and practical applications of these materials. Additionally, the accompanied science-in-action videos demonstrate the research experiments performed in laboratories.

civil engineering

Plotting a Horizontal Curve from Field Data

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