0
100% Satisfaction Guarantee
Amazing Value
Fast Shipping
Expert Customer Service
超长大体积混凝土结构跳仓法技术应用指南
$43.75
2.1.1
【条文】跳仓法(alternative bay construction method):在大体积混凝土结构施工中,在早期温度收缩应力较大的阶段,将超长的混凝土块体分为若干小块体间隔施工,经过短期的应力释放,在后期收缩应力较小的阶段再将若干小块体连成整体,依靠混凝土抗拉强度抵抗下一阶段的温度收缩应力的施工方法。
【条文说明】跳仓法施工的原理是基于“混凝土的开裂是一个涉及设计、施工、材料、环境及管理等的综合性问题,必须采取‘抗’与‘放’相结合的综合措施来预防”。“跳仓施工方法”虽然叫做“跳仓法”,但同时注意的是“抗”与“放”两个方面。
“放”的原理是基于目前在工业与民用建筑混凝土结构中,胶凝材料(水泥)水化放热速率较快,l~3d达到峰值,以后迅速下降,经过7~14d接近环境温度的特点,通过对现场施工进度、流水、场地的合理安排,先将超长结构划分为若干仓,相邻仓混凝土需要间隔7d后才能浇筑相连,通过跳仓问隔释放混凝土前期大部分温度变形与干燥收缩变形引起的约束应力。“放”的措施还包括初凝后多次细致的压光抹平,消除混凝土塑性阶段由大数量级的塑性收缩而产生的原始缺陷;浇筑后及时保温、保湿养护,让混凝土缓慢降温、缓慢干燥,从而利用混凝土的松弛性能,减小叠加应力。
“抗”的基本原则是在不增加胶凝材料用量的基础上,尽量提高混凝土的抗拉强度,主要从控制混凝土原材料性能、优化混凝土配合比人手,包括控制骨料粒径、级配与含泥量,尽量减小胶凝材料用量与用水量,控制混凝土入模温度与入模坍落度,以及混凝土“好好打”,保证混凝土的均质密实等方面。“抗”的措施还包括加强构造配筋,尤其是板角处的放射筋与大梁中的腰筋。结构整体封仓后,以混凝土本身的抗拉强度抵抗后期的收缩应力,整个过程“先放后抗”,后“以抗为主”。从约束收缩公式分析中,可得混凝土结构中的变形应力并不是随结构长度或约束情况而线性变化的,其值后总是趋近于某一极值,若混凝土的抗拉强度能尽量贴近这一值,则可极大地减小开裂。同时可看出应力总是与结构的降温幅度成正比(干燥收缩也等效为等量降温),故提高抗拉强度不能以增加水化热温升或干燥收缩为前提。
……
Shipping Overview:
• Shipping: Standard Domestic Shipping within the United States charges USD 4.99. Standard International Shipping from United Kingdom, Germany and Japan to the United States charges 14.99.
• Order Processing: Please allow 1-2 business days for order processing and preparation before shipment.
• Domestic Shipping: Orders within the U.S. are shipped via USPS or FedEx, depending on the origin of the product. The average transit time is 3-7 business days.
• International Shipping: Currently, we only ship within the USA.
• Tracking Information: Every order is trackable. You will receive a tracking number once your order has been shipped. Products may be shipped from various global fulfillment centers.
Shipping Delays:
Please note that shipping times may vary due to factors beyond our control, such as weather conditions, natural disasters, or peak holiday periods. While we strive to ensure timely delivery, the exact arrival time cannot be guaranteed and is managed by the shipping carrier.
Shipping Options:
Standard Delivery: Most orders are shipped within 3-7 business days. Larger items may utilize LTL shipping for safe handling.
Handling Time: We handle shipments on business days (Monday - Friday), with a preparation time of 1-2 days.
Additional Charges: Some items require additional shipping charges due to their size, weight, or special handling. These charges are specified on the product pages and are not eligible for shipping discounts.
Exclusions: Gift cards, packaging, taxes, and prior purchases do not count toward the minimum purchase requirement for free shipping. This offer is valid only for shipments to U.S. addresses, including Puerto Rico.
Delivery Details:
Estimates: Standard shipping within the US typically takes 3-7 business days. These are estimates and not guarantees.
Shipping Restrictions: We ship to all 50 states, Washington, DC, U.S. territories, and APO/FPO/DPO addresses. Shipping options vary based on the delivery address.
Remote Areas: Shipments to remote areas may incur additional charges or require pickup from a nearby shipping partner’s location.
Shipping Confirmation:
You will receive a shipping confirmation email with a tracking number as soon as your order is dispatched. If you do not receive this email immediately, please be assured that your items will arrive within the estimated delivery window provided at checkout.
Order Modifications:
If you need to cancel or modify your order, please contact our customer support immediately.
Issues with Delivery:
If your order shows as delivered but you have not received it, please contact the shipping carrier directly to resolve the issue. For persistent problems, contact our customer service at cs@everymarket.com.
Customer Support:
Our team is available 24/7 to assist you with any questions or concerns regarding your order. We are committed to ensuring a smooth shopping experience.
Return & Refund Policy Overview
Please review our return and refund policies below to ensure a smooth transaction process.
Return Policy
Duration: You have 30 days from receiving your item to initiate a return.
Condition: Items must be unworn, unwashed, with original tags and packaging intact.
Shipping Costs: Customers are responsible for return shipping costs.
Packaging: Ensure returned items are well-packaged to avoid damage during transit.
Tracking: Use a trackable and insured shipping method as we are not liable for items lost or damaged on return.
Initiating a Return: Contact us at cs@everymarket.com to start your return. We will provide a return shipping label and instructions upon approval. Returns without prior approval will not be accepted.
How to Return
Method: Returns must be sent back by mail to the address provided in the return instructions.
Return Label
Defective Products: Return labels are provided for defective items.
Non-Defective Returns: Customers are responsible for obtaining their return shipping label.
Product Conditions for Return
Eligible Products: Returns are only accepted for items in new condition.
Nonreturnable Items
Certain items are not eligible for return:
Electronic devices after 30 days (e.g., computers, laptops, Kindles)
Gift cards, prepaid game cards
Perishable goods, live insects, some jewelry, some health and personal care items
Customized or personalized products
Items with special shipping restrictions
Refund Policy
Window: Eligible products may be returned within 30 days of delivery for a refund.
Refund Method: Refunds are processed to the original payment method or as store credit for items purchased with gift cards.
Processing Time: Refunds are processed within 3-5 business days after we receive the return; please allow additional time for shipping and bank processing.
Claims
Inspect your order upon arrival and report any defects, damages, or incorrect items immediately to allow us to address the issue. For claims, contact our support team with details of the issue.
Exchange Policy
For the quickest service, return your original item and place a new order for the desired product once your return is accepted.
Return Address
EveryMarket Customer Service 2101 E Terra Ln, O'Fallon, MO 63366
Customer Support
Available 24/7 for any questions or assistance needed:
Phone: +1 636-312-5925
Email: cs@everymarket.com
Oops!
Sorry, it looks like some products are not available in selected quantity.
OK